Lighting on larval rearing ?

[Baboon_Science]

I have Clarks and Percula clowns producing.
I had success with the first batch of Percs in fairly bright light. That is standard T12 6400 about 6" over the tank.
I raised the light to lower the intensity with poor results.
Tank sides and base are covered so no reflection from there.

Was wondering what intensity was used in other larval tanks.
Thanks for the input.
John

 

[David M]

I'm guessing there is a pretty wide range of acceptable light level as this doesn't come up much and has never been a big issue here. That is probably why you aren't getting much response. They have to be able to see the food and you don't want to blind them, other than that it's probably not that critical. For example if they are "headstanding" on the bottom trying to dig thru the glass it's a good guess the light is too bright I have used everything from NOT12 6500 18" above the water line to HOT5 closer to 12", no difference that I can tell. JME, YMMV

 

[Baboon_Science]

Thanks
Just trying to troubleshoot a couple of poor starts after initial success. Parents are still in the low production stage (100-200 eggs) but all fry appear healthy. Good yolk, lots of energy. Phyto cultures good, rotifer cultures good, plenty of rotifers in larval tanks. Water same quality as initial successful spawns. Only real change was lighting which was much brighter for initial spawns??? Thought that I had too much light, so I reduced it to a single T12, 6400 about 24+ inches over the growout tank. Then poor growout. May have gone too far???

With the first lighting scheme, the never were doing the head in the sand (glass) thing so I guess I was ok with that.???

My only other problem was feeding enriched bbs too long after metamorphosis. The juveniles really get that crack baby appearance. After the enriched bbs is removed, they seem to go into withdrawl, just huddle together at the bottom for a few days. After that they seem to get back to being fish.

Thanks for the response. Would like to get this right with the relatively simple species before moving to the challenging....
John

 

[MarinaP]

<a href=showthread.php?s=&postid=9248675#post9248675 target=_blank>Originally posted</a> by Baboon_Science
Thanks

My only other problem was feeding enriched bbs too long after metamorphosis. The juveniles really get that crack baby appearance. After the enriched bbs is removed, they seem to go into withdrawl

Clarks and percs have large fry, I do not feed them BBS at all.

Fry goes from rots to O A1 mixed with frozen CP and crushed flakes.

I agree with David, light intensity is not a major contributing factor to larvae deaths, especially after a few days after hatch.

 

[Kmiec123]

I use stand. 4 ft. flor. fixture about 4 ft over tank. chromea 50 bulbs....

 

[Peter Schmiedel]

David,

does that also mean, that there is no benefits in covering all tank sites with dark material to ensure light coming ONLY from the top? I somehow can follow J.Wilkerson's thoughts about the eye sight which needs to get developed. But do you folks follow that for the first days ?

 

[Kmiec123]

I Do Peter

 

[David M]

My larvae tanks are painted black 3 sides and blue bottom. One (short) side is clear and I do not cover it at any time. However in a pinch I have used an unpainted/ uncovered tank and didn't notice any difference. Still, I buy the side light idea too and will continue using the painted tanks.

FWIW I find a blue bottom much easier to clean than black. My eyes are bad enough, no sense challenging them any more than I have to