Smelly Tank

[Mecula]

Hi,
I have a problem that I just cannot solve. My 75g smells terrible! I mean terrible! I can't figure out why. The inhabitants are: a 3" convict, 2 4" electric yellows, a 5" JD, 6 3" silver dollars, a 5" RTS, and 2 3" pictus'. I have had all these fish in the tank for several months. Never had a problem with disease or ick. I do weekly/bi-weekly water changes and clean the gravel at the same time and scrape the glass for algae. I have a 350 gph powerhead and a marineland 400 w/biowheel, 70 pounds of crushed coral gravel and 50 pounds of coral base rock. I feed the fish once a day, sometimes twice a day, with hikari floating pellets and occasionally tetra spirulina flake. The temp is at a constant 80 degrees. Any ideas? I love the tank and the fish, but Its getting so bad that I am contemplating getting rid of it beacause it is becoming a huge hassle and NOTHING works. Its in my bedroom so you can imagine my concern - Im at my wits end - Ive tried everything. Do they make fish cologne?

[fishmommy]

a bad smell can indicate trouble, so be sure to check both your Ammonia and Nitrate levels.
Assuming they are fine, adding activated carbon to your filter should take care of the odor.

[chc]

Also check the inside lip of your tank and any other areas that could have food residue or dead plant material on them. Keeping those areas clean keeps many odors away.

Still, fishmommy has it right. Bad odors are signs of water trouble. I would doubt your tank has fully cycled even though it has been set up for some time (it can take months even under good conditions to fully cycle). It is probably struggling with the bio-load.

Your fish are all hardy, so they could be handling the less than ideal conditions so far (but that only lasts so long).

You may not have enough bio-filtration (really, just the two biowheels of the Emperor are serving in that capacity). I would add an air driven sponge (Hydro Sponge IV or V), but if you don't like the look you could go with another Emperor or a canister (Fluval or Eheim). The sponge would be by far the cheapest way to go and it would serve its purpose just fine.

The only way to be sure (as noted by fishmommy) is to test for ammonia, nitrite, and nitrate. These are kits you should keep on hand, but most local fish stores will test water for you. Any readings in the ammonia and nitrite category would indicate a problem. If that is the case, I would minimize the water changes to 20% each week for some time and go easy on the gravel vacuuming. You'll be needing to disturb the bacterial populations as little as possible while the tank catches up.