pleco changing colors

Question
Hi there. The last few days I've noticed our tank water is cloudy (its a 30 gallon tank, not sure what 2 tell u abt filtration except that it hangs on the side & came w our hand-me-down tank). I am not sure how to go about cleaning it. We have had it running for the last 3 wks. A wk & a half ago both of our molly fish died w/in 24 hrs of one another. Now our pleco (which was black) has changed colors to a greyish tan color. He seems to be acting ok. I just noticed this now. The other fish in the tank are two bleeding heart tetras, a shark fish & a guppie as well as another pleco and 3 snails.
Is our fish sick? What should we do for him?? Also what can I do about changing the cloudy water? This is my 1st tank ever. Thanks for your help!

Answer
Hi Amanda,

If you did not cycle the tank before you added the fish then the fish are dying from the nitrogen cycling process that takes place in all newly set up tanks.  It's always advisable (and less work, and less frustration and doesn't take as long) to cycle a tank before adding fish.

You need to get a liquid drop test kit and test your tank water immediately for ammonia, nitrite and nitrates.  The cloudy water is due to the bacterial bloom, this is actually good and will go away on it's own, but ANY ammonia and nitrite (which will also cloud water) is bad and will stress, disease and finally kill fish.  This process can take 8-12 weeks to complete, much longer with fish present.  Fish will change colors with ammonia present.  I would also look for clamped fins on your other fish.

To save the fish when ammonia and nitrite are present you need to do daily 25% water changes and double dose the Seachem's Prime in place of your usual water conditioner.  Feed every 3 days and only small amounts.  Lower the temp to 75 F.  This will slow the process down but you have a chance to save your fish.  Now, you need to either return or re-home the guppies or the shark and my recommendation would be the shark.  Sharks and guppies are not compatible and there really aren't any freshwater sharks that are compatible with a 30 gallon tank.  Most need a minimum of 50-75+ gallons.

You also need to check to see what kind of plecos you have.  Most plecos get to be 2+ feet (yes feet!) long and need a 100+ gallon sized tank.  If they are a larger species I would return or re-home.  If you don't they will die from organ failure.  This is when they stop growing on the outside because the tank is too small and they've reached their maximum but the insides continue to grow until they fail.

Do not add anymore fish at all until you are completely cycled (this is when ammonia is 0, nitrites are 0 and nitrates are 5-20 ppm) and never use tap water for anything unless it's conditioned first as it will kill the beneficial bacteria that you are trying to accumulate.

If you need anything else please let me know.

Good luck : ) April M.