Amano Zoe growth rate

[eraserbones]

I know that a few people here have successfully raised Amano larvae. I've made a few attempts, and right now I have a hatch swimming around in about 30 gallons of green water (huge, I know, but a 40-breeder was handy.)

I transferred the larvae into saltwater about 10 days ago. My concern is that they look to my eye to be about the same size today as a week ago -- around 2mm tip to tail.

Is this normal, or should I worry that some conditions are wrong?

I seeded the water with Tetraselmis sp. and the water is nice and green -- there's light on 24/7. The tank is unheated, so the temperature is between 66 and 68F. Specific gravity a bit under 1.025. I'm not feeding any additional food so far -- I have a few sizes of GP available, but I get the impression that I should be worrying more about water quality than food supply.

[Mustafa]

The temperature sounds way too low to efficiently raise the larvae. They might not be eating at these temperatures. Raise the temperature to the mid 70s.

[badflash]

Yes, warmer is better, but don't worry that the zoes were harmed. I though a batch of mine had failed and I turned off the heat & lights for several weeks, only to find them still doing OK when I went to clean out the tank.

[carbon etc]

30 gallons... oh man. Good luck catching post-larvae when you get them.

You might want to drain it down so you're just using the bottom 5 gallons or so.

Though I'm finding skinny tall containers work better than squat containers just because the typical measuring devices for specific gravity are relatively tall.

[eraserbones]

OK, I bought a heater and raised the temp to about 82 degrees. The zoes are now growing rapidly, and seem more active as well.

I check on them by briefly switching off the light and shining a flashlight at a corner of the tank -- this attracts a few to a spot that I'm watching so I can see how they're doing. The larvae do seem to be less phototropic as they get older, though, so I may end up in suspense for the last week or so.

Does anyone have any idea how long the post-larvae can live in saltwater? I'm going out of town right about the time that (with luck) they'll be metamorphosing, and I'm wondering if I can deal with them when I get back, or if I need to leave painfully detailed instructions to my girlfriend about how to fish 'em out.

[Mustafa]

As long as you're not away for weeks at a time you can deal with them once you are back. In nature they take at least a few days to migrate back into freshwater anyway, so the postlarvae have a high salinity tolerance for a few days to a few weeks.