tank has cycled but still losing fish

[preston]

It has been 3 weeks since the setup of my tank. I originally set it up with 60 lbs of live rock and 16 damsels. LFS told me to use that many and they all died. A couple of them could not be retrieved due to being buried under the substrate that I added a day later. One week later, I ordered 200 lbs live rock online and received it within one day. It appeared that the rock was shipped promptly from Fiji and arrived still moist, so I put it in and after a couple of days noticed the ammonia level dropped and nitirite slightly rose. About 5 days later, the levels for ammonia were 0 and nitrite were 0 with nitrate being low as well. The ph is around 8.2 and the salinity is around 1.022. I purchased 3 more damsels. 2 days later 2 of the damsels have died, I cannot locate them, and the other is looking pale. The water levels are holding steady at the previous rates and I still have diatoms blooming. I have 2 computer case fans blowing across the top to obtain 79-80 degrees which evaporates about 2 gals per day. I replace with tap water treated with Novaqua. I am trying to figure out why these damsels are dying? Is my tank still cycling? Shouldn't the damsels be able to handle this? Thanks for your help.

 

[ryebread]

How big is your tank?!?! I would not think you would want to cycle a tank with sixteen fish unless it was maybe 300-500 gallons. Your LFS may have wanted to unload some mean damsels on you. If the damsel that you have left is pale you may be in trouble. Have you noticed any of the fish rubbing or scraping on the rock or sand bed? Your water is probably fouled due to all of the fish deaths and not removing the deceased. Many questions on this case.

 

[broomer5]

preston
I a 175 gallon tank, you could have easily cycled it with the 265 pounds of live rock - and no real need to add the damsels.
Did your LFS person realize you planned on adding this much live rock ?
If so, and they still advised to use damsels - then shame on them.
Having a couple dead decaying fish carcasses under your substrate, and now a couple more rotting in your stack of rock, is not the best either. Your substrate may develop a small nutrient pocket in those areas until the bacteria and natural processes consume and convert the dead fish.
I'd continue to monitor your tankwater, and follow any changes in your ammonia/nitrites/nitrates.
No telling how long it will take these fish bodies to decompose.
But I would hesitate to add any more fish at this time.
If you water quality remains somewhat stable, a few hermit crabs would locate and take care of the dead damsels in the rock work, but I'm unsure what to do about the dead ones that are buried. Eventually they'll rot away, but I'm not sure how long that will take, nor any short-term~long-term affects that may have on your tank.

 

[aileena]

Go and get yourself about 20 blue hermit crabs they are carnivores and will eat anything and everything. They should be able to located any dead fish and devour them instantly. Don't go crazy and add 50 or 100 though cause later you will want to get red hermits which are a lot nicer and blue hermits fight for shells with everyone.
If you have crushed coral tey to vacuum the spots that are not covered with live rock. Next are you aclimating these fish? Don't just dump them in the water. Keep on ckecking your parameters, with that big a tank those blue hermits and a good protien skimmer with some vacuuming those dead damsels will surface eventually. Try adding 3 large chromis, large enough to where if they die you can find them. GOOD LUCK