cichlids hanging out at the top

Question
Hi Chris,
  I have a 55 gal. cichlid aquarium peacocks and haps. 15 fish total ph 8.0, nitrate 0   nitrite 0, alk. high, total  hardness 300.  I did a 50% water change saturday. this morning all of my fish are hanging out at the top of the aquarium. I tried to feed them - not hungry. Water tests great. I have a eheim professional 2 canister filter that was changed 3 weeks ago.
what could be wrong?
                             Please help,
                                   vicki

Answer
Hi Vicki;

Look for parasites like ICH. With such a major water change it could shock them enough to be susceptible to something like that. Parasites and other pathogens are present in our tanks all the time. They are opportunists so will attack weakened fish when given the opportunity. Always use a water conditioner that removes chlorine and chloramine as well as helping the fish with stress. It's best to change no more than 25% in any 24 hour period.

Also look at the color of the gills. If they look pale, dark, anything other than usual. Not the gill covers but the gills inside the gill covers. Look to see if there is any fuzziness or tattering of the gills too.

It's also possible there was an ammonia and/or nitrite spike that was gone before you could get a test result on it. Changing the filter media will easily cause that. It could have damaged their gills and now they are trying to recover. Filters should not be "changed" but only rinsed. Only replace the media if it is literally falling apart. The filter media is where the beneficial bacteria grows that consumes fish waste toxins. When removed it has to grow back again and it can be very slow. I don't even use carbon or charcoal at all anymore. It absorbs toxins for 3 to 7 days and then can release those toxins back into the water again once full. I replaced those chambers of my Fluval canister with ceramic beads and other beneficial bacteria harboring media. I rinse them about every 2 to 4 months and make regular water changes. My fish do quite well. They key is to vacuum the gravel every month or so and make 25% water changes every week. Changing water more often and smaller amounts of water at a time is the key. It keeps the water chemistry more stable and less "rollercoaster" like.

Could there have been a toxin in the air that got into the tank? If so, then adding carbon for 3 days would be good. Then throw it away. Air freshener, hair spray, bug spray, window cleaner, furniture polish, etc.can poison the fish. Change 25% of the water every day for 3 or 4 days to dilute whatever could be in there. Or, could the filter media you just added have absorbed something? Anything it was exposed to before you got it could now be in the tank. Or, could it have been rinsed in something that accidently had detergent, soap or other toxins in it? If so, replace the carbon and pads with more new ones. Maybe from a different store just in case. Our wholesalers would sometimes get some pretty neglectful packers. These wholesale distributors have all kinds of products like flea spray, aquarium water conditioners, dog shampoo, aquarium filter media, etc. If they are boxed together they can leak onto each other and, well....you get the point. It just happens sometimes.

Let me know what you think. Hopefully we can figure out what's going on with those poor guys.

At Your Service;
Chris Robbins