Fish tube, again

We re-installed the fish tube, and it seems to be much more popular this time around! Everybody's had a turn at it: the rasboras, panda cory, Amano shrimp, and even our nerite snail! The snail must have climbed up on a plant or something, because the tube doesn't touch the walls of the tank.

There is regularly at least one rasbora in the tube. It's usually a different rasbora each day, which is a relief.

Southern California adventures

Lots of adventures over the last two weeks!

Fish relocation

Yesterday we moved the fish down to my apartment in LA.

Shrimps

Yesterday I got some new inhabitants for the tank I'm setting up here!

New cowfish

During the move, we discovered that one of the cowfishes (our name for our Panda Cories, which look and act like cows) had crossed over the fish tube without our noticing and died in the new tank.

Worried that our last remaining cowfish would get lonely, we went up to Ocean Aquarium in SF last Sunday to get him some friends - two more panda cories.

They seem to be getting along well. Despite the old cowfish being significantly larger than the new ones, they are herding together. They appear more active at night, when the aquarium lights are off. During they day, they mostly swim slowly around the plant growth, but at night we've seen them going up and down the sides of the glass. They're very cute together!

Fish Tube

After talking about it for a long time, we finally implemented the fish tube: a fish-sized tube connecting our two 10-gallon aquaria.

February: We add gravel and plants to set up our second tank.

March-April: Many water tests on the new tank to ensure it's stabilized. One treatment of erythromycin in response to a blue-green algae bloom.

April-May: More water tests.

Date	Tank	NH4	NO3	PO4	pH	GH	KH	Notes
4/30	Old	0	5	0.5	7.6	5
	New	0	5	0.5	7.6	4		20% water change, started erythromycin
	Tap water				7.6	3
5/1	New							Nitrogen fertilizer, erythromycin
5/2	New							20% water change, erythromycin
5/3	New							erythromycin
5/4	New	0	10	2	7.2	5	4	20% water change, added nitrogen
5/7	New	0	5	1	7.6			20% water change, added nitrogen
5/11	Old	0	5	0.25	7.6	4
	New	0.25	5	0.5	7.6	5
5/19								Fish tube, 25% water change
5/22	New	0	5	0.25	7.6	5	4	Two tanks hopefully equilibrated

The Fish Tube

The fish tube is a clear rectangular tube, 1.75" x 2.25" in cross section (inside dimensions), constructed of acrylic held together with Loctite 3321 UV adhesive. It is shaped like an inverted U with a total length of 15" (measured along the center line).

It bridges the two tanks and provides a path through which our fish can swim from one to the other. Unfortunately, this is the furthest into the tube that the fish have ventured so far:

I also hoped the tube would allow stuff to diffuse between the two tanks. I tried to verify this using some quick calculations:

Using a published diffusion rate of 1.8×10^-9 m²/s for ammonium at 25°C and approximating the fish tube as 0.38 m long, Fick's law gives us J = -(4.7×10^-9 m/s)Δφ, where J is the diffusion flux (mol/m²s, say) and Δφ is the concentration difference (mol/m³). The tube has a 2.5 × 10^-3 m² cross-sectional area and each tank holds 40 L, which gives us dφ/dt = (0.063 m^-1)J for each tank, ultimately yielding:

dΔφ/dt = -(5.9×10^-10 s^-1)Δφ

which has a time constant of 54 years. Looks like molecular diffusion is not a significant factor. So we have to rely on macroscopic mixing due to flow within the tube, which I'm not able to characterize so easily. But I think it's probably happening!

Update (May 24): One rasbora in the new tank! He must have...gotten lost or something. But perhaps they'll start getting used to inter-aquarium travel!

Update (May 26): We decided the rasbora in the new tank looked pretty miserable being by himself, and probably wasn't there of his own volition. We chased him into the mouth of the tube using a net, but he was very reluctant to go further up the tube (i.e., above the water line). We started pushing the net into the tube, which finally encouraged him to get over his fears and enter the tube. He looked very confused, then swam quickly across the tube and back down into the old tank.

Update (June 5): Getting ready for our China trip. Stuffed some stem plants into the tube to prevent the fish from getting lost again. To keep the water chemistry more stable, I added a drain tube to siphon water from the new tank's filter into the old tank, creating circulation. A little worried because blue-green algae continues to be a problem in the new tank, but I am hoping that joining the two will provide the proper balance of nutrients to encourage plant rather than algae growth. Of course, it could go the other way, and we could come home to find both tanks overrun with cyanobacteria...

Update (July 23): Cyanobacteria still abounds in the new tank, though the old tank seems unaffected. I put snail into the new tank to eat the brown algae. He cleans it off very effectively, but he random-walks around the tank, so there are many areas left uncleaned.

The night before last, we found a rasbora sleeping in the fish tube! He was the slightly off-kilter one. We didn't know if figured out how the fish tube works or if he was just lost. In the morning, he was back in the old tank.

Last night, he was back in the tube! And later that night, he was sleeping in the new tank. This morning, though, he was pretty freaked out and trying to swim back to the old tank by running into the glass. I fed him, but he was too freaked out to eat. I chased him into the tube and had to push the net into the tube to get him to go above the water line. He's back in the old tank now.

Update (July 26): Yesterday the Oto made his way through the fish tube! He spent most of the day swimming frantically in the new tank. That night, he found his way back. At the same time, a rasbora (probably the same rasbora as before) spent the night in the tube and was in the new tank in the morning. He's still there.

New tank update

March 24:

New tank is struggling a bit. Blue-green algae has started to grow.

• Ammonium: 0 ppm
• Nitrate: 20 ppm
• Phosphate: 2.0 ppm
• pH: >= 7.6

Nitrate and phosphate are quite high, which is probably what spurred the blue-green algae growth. Perhaps it is leaching out of the soil? I can't imagine where else it could be coming from in that quantity.

Vacuumed the gravel and added some trumpet snails. Transplanted more stem plants from the old tank.

The old tank is holding steady in nitrate and phosphate, but ammonium is a tad high:

• Ammonium: 0.25 ppm
• Nitrate: 10 ppm
• Phosphate: 0.5 ppm
• pH: >= 7.6

Vacuumed the gravel here, too.

March 30:

Old tank is still 0.25 ppm ammonium. It seems otherwise fine.

Blue-green algae is coming in pretty thick in the new tank. Cleared out some manually and performed a 50% water change (nitrate 10 ppm and phosphate 1 ppm after the change). Started dosing Erythromycin.

Early April:

Water test after we finished dosing Erythromicin. Can't find the results now (wrote them down on a piece of paper), but I remember the new tank had high ammonium (0.5 ppm) and low pH (7.2) but everything else was typical values. Performed 50% water change.

April 14:

New tank:

• Ammonium: 0 ppm
• Nitrate: 10 ppm
• Phosphate: 1.0 ppm
• pH: 6.8

Didn't retest the old tank except to verify that its pH is still >= 7.6

Performed a small water change and will start trying to equalize the two tanks.

April 23:

New tank:

• Ammonium: 0.25 ppm
• Nitrate: 10 ppm
• Phoshate: 0.5 ppm
• pH: 7.6
• KH: 4°
• GH: 4°

Old tank:

• Ammonium: 0.0 ppm
• Nitrate: 0 ppm
• Phosphate: 0.25 ppm
• pH: 7.6
• KH: 5°
• GH: 5°

As you can see, we got a hardness test kit. I was concerned because the pH in the new tank was low earlier this month, but its hardness now indicates adequate buffering capacity. Strange that the old tank's nitrate is so low...I wonder if it's measurement error. I've always been suspicious of that second bottle of nitrate test reagent because you have to shake it before use.

Performed a 20% water change and am mixing water from the old tank into the new one. Possible signs of a blue-green algae revival in the new tank.

Fish tank setup update

Old tank:

• 10 ppm nitrate
• 0.25 ppm ammonium
• 0.5 ppm phosphate
• pH 7.6

New tank:

• 20 ppm nitrate
• 0.5 ppm ammonium
• 0.5 ppm phosphate
• pH 7.6

The ammonium in the old tank is a bit troubling; perhaps the nitrifying bacteria population isn't big enough without that giant floating plant mass acting as a nitrogen sink. Or maybe uprooting the transplanted crypts released underground ammonia? That seems unlikely. Anyways, the animals (nerite snail, shrimp, oto, 2 panda cories, 5 harlequin rasboras) seem to be doing fine.

Initially I thought the ammonium and nitrate in the new tank must have come from the soil, but ammonium levels have been around 0.5 ppm for a week now. I hope it's not steadily leaching from the soil (through 2" of sand); I think it's more likely to be decaying algae on the rock and the log (leftover algae from the old tank, dessicating for almost a year). The new grass seems to be doing all right; some of it has withered away but that just means the remaining leaves are thriving, right? Crypts look all right, except the leaves that I broke while transplanting it - those have died. Stem plants that I took from the old tank are all doing very well. The ones I'd taken from the floating plant mass don't look so good. They started out with smaller leaves, and now many of them have yellowed (probably dying) shoot apical meristems.

Today I did a 50% water change of the new tank and a 20% change of the old tank. 

Fishes! An illustrated history, part 6

It's been almost a year since fish history part 5. Lots has happened in the meantime.

2010 Feb 13

We have a sad-looking java fern on the far left, some riccia tied to rocks, a few stem plants of different varieties (there's fuzzy plant, leafy plant, clover plant, and Stem Plant), some crypts in the foreground, a sword plant in the far back, an anubias over towards the right, and a banana plant behind it. There's also an anubias nana in the back right (it's not doing very well), as well as some four-leaf clover and pygmy chain sword scattered around (the clover is doing pretty well, but the chain sword is being shaded by the crypts).

2010 Mar 15

The riccia has grown intensely and is coming loose. Java fern is making a comeback, the crypts continue to thicken, and Stem Plant is growing quite long. The other stem plants are not doing as well. The last of the broad-leafed purple not-actually-an-aquatic-plant in the left is disintegrating. Nana has put out some new leaves.

2010 Apr 13

One riccia bunch has separated for good; the other is making good progress in that direction. Banana plant has sent up a pad to the surface, joining Stem Plant in forming a canopy over the aquarium.

2010 Apr 29
The littlest cowfish died :(

2010 May 16

Banana plant has sent a second pad up to the surface. Both are on some heavy-duty stems, maybe 2 mm in diameter. The sword plant in the back has put out new leaves, but its older leaves are growing fuzzy with algae and starting to die off.

2010 May 31

Did a lot of pruning. I trimmed the stem plants to the aquarium height and took out the riccia. The extra plants are all in the second tank now, acting as a nitrogen sink. With the mess of Stem Plant out of the way, we can see the other stem plants aren't doing as well. Fuzzy plant hasn't grown at all in the last few months, the clover stem plant is down to a single stalk now, and the leafy stem plant is losing old leaves without putting out new ones.

2010 June 1
A shrimp died :(  Also, we try to discipline the belligerent two-stripe rasbora, but that fails.

2010 June 10
Two more fish deaths: loner rasbora and old oto.

2010 Aug 28

The pads that banana plant sent up to the surface have come detached and I removed them. Java fern is quite full now, and the crypts are doing very well. I've been keeping Stem Plant trimmed. The other stem plants are slowly dying...I don't know what to do about that.

2010 Sep. 19
The big move! Pride Rock (the rock you can see jutting out in the picture above) has fallen over and the terrain has generally become flatter.

2010 Nov 13

Not much has changed. Terrain continues to get flatter; I think the army of trumpet snails is at blame. The clover stem plant and the leafy stem plant are gone, leaving only Stem Plant and two stalks of fuzzy plant.

2011 Feb 21
Banana plant has floated away and the fuzzy plants were overcome with algae. But today we took the next step towards the fish tube, a contraption I first alluded to almost a year ago!

I used xyster.com's TimeLapse app (v4.1 for iPhone 4) to make these videos.

That first segment was 2 hours. This next one runs until the iPhone battery dies:

No captions above; I'm just adding more clean water and straightening the plants.

And that leaves us with this:

Ammonium is high (1 ppm), so I'm going to let it go for a few days before reintroducing the trumpet snails (they're hanging out in a bucket right now) and setting up the fish tube. It'll be interesting to see the progression of this tank!

2011 Feb 22
Ammonium down to 0.5 ppm now. I think that initial spike came from the soil; hopefully the 2" of sand will keep that from diffusing out too fast. The plants are also supposed to absorb ammonium preferentially over other forms of nitrogen.

I Love Blue Sea

A while back, we got a Groupon for i love blue sea, a San Francisco (they also ship nationwide) seafood distributor that provides incredibly fresh (sushi quality) sustainable seafood at good prices (definitely cheaper than the local supermarket for comparable items).

Over the weekend, we placed an order and drove up to the city to pick it up (their warehouse is open for pickups from 12-1pm, Monday - Saturday). They filled our little cooler and with ice and seafood. With the pickup discount, we got:

• 1 dozen Hood Canal Bay oysters ($16)
• 1.5 lb Hawaiian pole-and-line albacore tuna ($20)
• 1 lb Prince Edward Island mussels ($6)

The oysters were amazing. Difficult to open (we both ended up stabbing ourselves with a 3" paring knife), but delicious.

It turns out we were storing them a bit colder than optimal (ideal is 35-40 °F, with adequate oxygen supply), but we ate them over the course of 36 hours without ill effect.

At only $6, I think the mussels were best deal of all. We ate a few raw (I don't recommend it - they're kinda bitter) and boiled the rest to make a sauce for linguine (olive oil, white wine, mussels, bell pepper, tomato). All the mussels were alive, and there was enough for 2 plates like this:

That's lightly seared tuna on top, because we had a ton of it. Per pound, it's a great price, but the 1.5 lb minimum order puts us into a region of diminishing returns.

It's not actually green; that's unfortunately how fluorescent light comes out on film. Anyways, we made a lot of tuna-and-avocado rolls with the winter-ripening bacon avocado we'd gotten from the farmer's market by Moss Landing. It was awesome.

We then had seared tuna for lunch the next day. The searing adds a welcome complexity of taste to the surface, while the bulk maintains the texture of the raw fish. We want the surface temperature to reach 150°C for the Maillard reaction, but want to minimize the region that exceeds 60°C (turns opaque and flaky). So if raw albacore tuna has a thermal diffusivity of 0.15 mm²/s and we start at an initial condition of 0°C, this is starting to sound like a parabolic PDE...

The boundary condition is problematic. Making it isothermal with the pan defeats the purpose of our modeling; perhaps constant heat flux is more appropriate. Furthermore, the meat's heat capacity becomes ∞ for a while when it reaches 100°C, but we can approximate this effect by adding f_MΔH_vap/C_P to the goal temperature, where f_M is the tuna's moisture content (63%), ΔH_vap is water's heat of vaporization (2257 J/g), and C_P is the specific heat of tuna (3.1 J/g K). This gives us a target surface temp of 610°C...

Okay, looks like ΔH_vap is a bigger player than I initially thought. Within the fish, conduction would be best modeled with an isothermal boundary condition at 100°C. Using the semi-infinite slab solutions (which is actually just an ODE after nondimensionalization), we get T(x,t) = T_surfaceerfc(x/√4αt). We're interested in when/where T = 60°C, i.e. x/√4αt = erfc^-1(60/100) = 0.37. For x in mm and t in s, this comes out to x = 0.29√t. So that ~1 mm "cooked" layer in the picture would have taken 12 sec.

The next question is to find how long it takes for the fish surface to reach 150°C. Unfortunately this requires more information, including the heat flux into the surface and some sort of diffusion length for the movement of moisture from the bulk into the rapidly-dehydrating surface. These are the primary factors in determining how long it will take to brown the surface.

As a side note, I have got to figure out how to put LaTeX into blog posts; formatting formulae in HTML is terribly unwieldy.

Anyways, we still had leftover fish after the seared tuna lunch, so we've salted the rest in much the same way as we did before.

Adventures with f/1.8, macro, and lighting

Got another batch back from Snapfish! This roll was Fujicolor 400 Superia, again. I've also started keeping an exposure log, which is a pretty sorry substitute for EXIF tags. The analog world: pure barbarism!

This one was shot with my new 50mm lens wide open at f/1.8. It's illuminated by sunlight through a curtain to the right. And you can see how shallow the depth of field is! Not even the whole avocado can be in focus. Also, it turns out I'm not great at judging focus through my camera's viewfinder (Nikon N65). I should start using autofocus, especially for stationary shots like this.

Also, what happened to this avacado pit? The avacado tasted a little funny, too. But we ate it anyways!

These two show the fish tank taken at 28mm f/3.5 (top) and 50mm f/1.8 (bottom). Faster shutter speed (1/30 vs. 1/8, both hand-held) accounts for the increased sharpness.
Other notes: bright streaks in top photo are reflections of bright room in tank glass. Better to take these photos at night. Also, some exposure compensation (say, -1 stop) may be in order.

  

  

  

These are taken with a +4 close-up filter at 50mm f/1.8, so the depth of field is quite short. The close-up filter is 58mm diameter to fit the 28-80mm zoom lens, but the 50mm prime lens has a 52mm diameter thread, so I had to hold the two together by hand. These we taken with manual focus, which means they are a bit out of focus.

80mm, f/5.6, afternoon light. Dark bird against illuminated leaves. Not great.

 50mm, f/4.8, 1/90, with flash. Super washed out, but why?

80mm, 1/90, with flash, noon light. The fill flash is much more subtle in this shot. I think it's because the zoom lens is an AF-D model, whereas the 50mm prime lens is an older non-D model. The -D version provides focus distance to the camera, which uses it for metering (including TTL flash metering). I think this is the type of situation it's designed to compensate for. Still, doesn't illuminate the bird as I'd like.

80mm, 1/90, f/8, during a 30-minute window where the late afternoon sunlight illuminates the feeder directly. I guess photography is more of a patience game than I had thought, because this is so much better looking than the other shots. Next time, maybe I'll try taping a white card to the railing for fill lighting and shooting from a lower angle to reduce background clutter.
This also seems like a pretty good shutter speed for blurred wing motion. Since it is the camera's flash sync speed, it must take ~10 ms for the shutter curtain to traverse the frame. So if the hummingbird fills 1/5 the frame, it'll take 2 ms + t_exp to capture him. Assuming a 55 Hz hovering wingbeat typical of the ruby-throated hummingbird, the wings will complete 0.66 cycles at 1/90, 0.33 cycles at 1/250, and 0.17 at 1/1000. So without a flash, it's pretty hopeless to try to freeze wing motion. Speaking of shutter speeds, I think rolling shutter motion distortion effects are kinda interesting, though I'm probably not going to see it on hummingbird wings.

Film back from Snapfish

These came back from Snapfish Thursday (3 day turnaround, just like York Photo). I think they did a slightly better job with dust and scratches. Like the York scans, the brightness on these were also off (I did some software adjustments):

With the 400 speed film, I tried a shot of the fish tank, which is lit by a single 20W fluorescent tube. I think the shutter speed was 1/8 or 1/10.

I really ought to start writing down the exposure information for each shot. I don't remember anything about the shutter speed or lighting.

 The next few photos are from the Palo Alto Foothills Park.

SC contemplating some lichen (Alectoria sarmentosa, I think)

 A duck thing nibbling aquatic stem plants.

The colors on a lot of these came out really muted...I wonder what I can do about that.

Here's that hill I took a picture of in HDR mode on my iPhone. Colors look a lot better here, and I guess the fact that this came out means the film's dynamic range is wider than the iPhone's.

This came out very sharp. Maybe this means my other photos are out of focus...

I keep finding myself distracted by the hard edges on the out-of-focus twigs in the background.

The film definitely renders color differently than digital. I haven't figured out yet under what circumstances that's a good thing...

Rasbora update

Saw some interesting behavior in two of our rasboras today:

That's the big fish (two-stripe fish), chasing around one of the smaller fish, possibly trying to mate with her and probably doing it wrong. I took this video on my iPhone 4 - the camera on it is pretty slick.

Monterey aquarium members

Went to Monterey aquarium today. Buying the student membership breaks even after two visits, so we decided to get the membership. Now we can go whenever we want! Well, we'll still have the 160 mi / 7 gal / $21 transportation cost, but that's not too bad.

We spent a lot of time looking at the cuttlefish. They're much bigger than the last time we saw them, and they're much more mature now. When they were young, there was a couple fish in the tank with them and they were pretty intimidated by the fish. When startled, they'd jet backwards, and if this trajectory intersected the wall, the bump would startle them into jetting backwards again, right into the same wall. We also got to see them get fed, which was very cool to see.

Anyways, they're big now. They have the tank all to themselves and are now fighting amongst each other. It looks like they're getting pickier about their food, too, because there was lots of food lying around the tank being slowly scavenged by hermit crabs and worm things.

We dropped in on the octopi a few times, but both were inactive. One was pretending (very successfully) to be a rock, and the other was sucked up against the top corner of the glass.

The new flamingo exhibit was nice, but I miss the planted tanks in the old river otter exhibit. We saw a spoonbill standing on a mangrove eating things off its leaves, which was rather odd. The terrariums seemed a little small for birds, though. The exhibit was accompanied by after-school-special anti-carbon messages, which is starting to feel a little heavy-handed, but I think the target there is right. Also apparently the Seafood Watch pamphlets are working, at least according to the aquarium organizers, so that's pretty cool.

Hopping fishes!

We saw them feeding the big kelp tank. A diver went in and all the fishes (including the rockfishes who look dead when they drift along in strange orientations) swam up to her to get the food (restaurant-quality squid, apparently) she was handing out.

Afterwards we talked to the dude narrating the feeding. Learned some pretty cool things. The kelp reproduces in the tank (and grows up, which he calls "recruitment") and grows pretty fast (couple inches a day) in the peak season. The tank water comes from the bay; filtered during the day for clarity, but raw water at night for the nutrients.

Lots of active predation in the tank. Scavengers keep it clear of dead fishes. The fishes reproduce, but other fishes eat the eggs, so there isn't recruitment. Other fishes eat sea urchins, which could pose a problem for the kelp.

Fishes school by size, so you'll have mixed species in a single school. When other species sneak into the tank, they can have trouble when the outgrow the species they sneaked in as...their larger size marks them for predation.

The first set of tuna in the big tank had unnaturally short life spans, and their autopsy showed it was due to cholesterol from the rich diet they were being fed. Oh noes! So they started feeding them healthier food (squid), and life span increased.

Baby jellyfish in a tube

Whelks, with feeding tubes

We also bought some strawberries and artichokes at a farmers' market on the drive down. The strawberries were meh and rotting quite rapidly (a day in a hot car didn't help). The small artichokes (10 for $1, which was what drew us in) are okay; not much of a heart but also not much of a choke. The big artichokes have a tasty heart, but what a strange vegetable to eat!

Updates from the past week

Abbreviated posts:

Saturday (6/5)
Helicopter test flight with Aaron and Max. Had some close calls myself (lost track of heading and then the wind took it far away where I couldn't see it very well), but managed to keep the blades away from danger. Let Aaron fly it. He's got some co-axial experience and some simulator time (well, 5 minutes worth), and was much better at holding a hover than I was. Unfortunately ended with crashing into a bike tire. Broke the landing gear.

Glued the landing gear back in place, replaced the feathering shaft (dunno exactly when it got bent). Lately have been seeing the system act glitchy; I don't know why and I don't even know where to start looking. The most plausible scenario I can think of is the increased vibrations (due to unbalanced blades or other damage) putting excessive noise into the AHRS.

Tuesday (6/8)
A rasbora died! :( It was the loner fish who looked like he had tail damage, possibly as a result of fights. His tail was completely gone when I found him. And that morning, the other fishes were strangely quiet (they usually fight in the morning), huddled together in the center of the tank.

Wednesday (6/9)
Muir Beach and pirates' cove with Max, Bryce, and Nick. A really windy spot. I climb a boulder. Throwing rocks. Fiji water and expensive sammiches from JJ&F.

Thursday (6/10)
Old oto (a.k.a. fat oto) died :( Afterwards, we changed the water, because that's all that we really can do, but water tests didn't show anything particularly out of the ordinary. But it is a troubling spate of fish deaths. While changing the water, did notice the thin tube (between the two tanks) was clogged by a wayward snail.

Friday (6/11)
Family (parents and brother) in town! Presented the helicopter to my dad. Took it out for a test run, but ended up crashing the landing. I think it was a level landing, just a little hard, and then the previously-broken landing gear broke, causing the helicopter to roll over on that side until the blades struck the ground. Feathering shaft is noticeably bent. Damnit. Felt pretty bad about it all.

Went to Mediterranean Wraps for lunch, then made beef Stroganov for dinner. Used beef flank this time, which I didn't like as much as the tenderloin we used last time. Also had watermelon, which was a great treat in the hot weather.

Saturday (6/12)
Went up to Muir Woods and walked around (Hillside trail, ~2 mi). Big sequoias. Very straight. Asexual reproduction through burls, which cause a ring of clonal redwoods to grow around the burnt-out stump of the parent. Also, bendy phototroping bay laurels, which seem to be able to grow out of dead logs. And redwood sorrels, which sleep in the sun and open up in the shade (except for some lazy ones we saw napping in the shade).

The hilly drive up put higher demands on the engine than I'd seen before. Even on the highway, there were parts where full throttle in fifth just wasn't enough (well, not quite WOT...I wanted to avoid the rich burn and other power-boosting tweaks that happen up there).

This whole weekend I've been feeling the car act a little more sluggish than usual. Due to the high correlation between input variables, I can't tell whether this is due to increased passenger mass (~15% of the vehicle weight) or the air conditioner load. Actually, now that I think about it, in addition to slower acceleration, I've also noticed longer stopping distances (which can only be explained by increased mass). An unrelated observation: the A/C is more powerful at higher engine speeds.

Also went to the Golden Gate Bridge visitor center, and the Richmond district's Chinatown. Came back to have dinner with family friends at Jade Palace/Duck restaurant.

Sunday (6/13)
Got up early to get a Master's hood from the bookstore. Graduation today! Turns out the Master's robe is slightly different from the Bachelor's: it's got extensions from the bottoms of the sleeves, as if you might have 2 forearms like the Gatekeepers from Schlock Mercenary. Skipped the commencement ceremony, though; just went to the department ceremony.

Afterwards, went to the San Jose Tech Museum; it was free second Sundays, which was cool, and we spent the whole time going through the exhibits. Not much new since the last time I've been there (there was a Genghis Kahn exhibit, but it was kinda expensive and the rest of the family wasn't very interested), but it was much less crowded than I've seen before, which was nice.

Oh - check engine light came on again; still the neutral position switch and knock sensor, so I just cleared it again.

Badfish, and goodbye to shrimp

Rasboras were fighting again today. One of them had some scale damage near the caudal fin, so it seemed like the fighting could be pretty serious. We identified one (two-stripe fish) who seemed to be a primary instigator, so we netted him out to put into solitary confinement (a plastic jar floating in the main tank).

As soon as we took him out, another fish seemed to take his role in terrorizing the other fish. We were getting ready to take him out when I found one of the shrimp (the lighter-colored one) lying dead on his side, which was quite a surprise because the shrimp have been out and about and growing quite large.

We immediately did a water test, and as I was waiting for the results (ammonia < 0.25 ppm, nitrate 10 ppm, phosphate 0.5 ppm) I hear a tiny splash and look up to see a guilty-looking rasbora at the surface of the water. He immediately darts for cover. Upon further inspection, the jail cell is empty! Yet another instance of jumping rasbora...this is why we have to keep the lid closed.

More underwater gardening, and finding a long-lost fish

Did more pruning of the stem plants in the aquarium today; now you can actually see the water surface. And more importantly, the rasboras will be able to get food from the surface.

The rasboras did some fighting right after I finished with the plants. They flare all their fins out and sidle up to each other (parallel) or circle each other (antiparallel) until one lunges for the other and the other runs. They eventually calmed down. With more open space now, we hope they'll start schooling together again.

We also found both otos...it's been a long time since we've seen both of them at the same time (and it's hard to tell which is which without a direct comparison) that I'd declared one missing, presumed dead. Here's one (I think this is the older oto) sucked onto the glass being fat:

And here's the other one chilling with a shrimp along the back wall: