Polluted Tank - Help!

[Diddakai]

The water in my tank is crystal clear and my fish seem very happy and active, but I took a water sample to the shop that's been helping me set up my tank today and it's very polluted.

We have 5 small fish in a tank that we have been told could accommodate 18 small fish, so it's not overcrowding. We feed them every other day and then only a small amount, so I don't think it's overfeeding. The aquarium is only 2 weeks old - we were told to leave it empty for a week to give the filter chance to build up its bacteria, then add our fish 5 at a time. We have two catfish, two loach and a crab, with live plants (that the crab is taking great delight in destroying ). We remove dead and floating leaves as soon as we spot them, although dying leaves isn't as much a problem anymore.

The man in the shop said to do a 50% water change, don't feed them for 3 days then go back for another test. We hardly feed them anyway - they won't die, will they? And where's the pollution coming from? We have sand at the bottom and two pieces of aquarium wood, it's all been in since day one with nothing added, the temperature is a pretty constant 75-ish, we have lights, there's no algae, we have the odd tiny snail but the crab eats them when he sees them... We can't add any more fish until the problem clears up and I'm bored of these ones now! (I'm joking!)

Thanks

D x

 

[Fella]

The water in my tank is crystal clear and my fish seem very happy and active, but I took a water sample to the shop that's been helping me set up my tank today and it's very polluted.

We have 5 small fish in a tank that we have been told could accommodate 18 small fish, so it's not overcrowding. We feed them every other day and then only a small amount, so I don't think it's overfeeding. The aquarium is only 2 weeks old - we were told to leave it empty for a week to give the filter chance to build up its bacteria, then add our fish 5 at a time. We have two catfish, two loach and a crab, with live plants (that the crab is taking great delight in destroying ). We remove dead and floating leaves as soon as we spot them, although dying leaves isn't as much a problem anymore.

The man in the shop said to do a 50% water change, don't feed them for 3 days then go back for another test. We hardly feed them anyway - they won't die, will they? And where's the pollution coming from? We have sand at the bottom and two pieces of aquarium wood, it's all been in since day one with nothing added, the temperature is a pretty constant 75-ish, we have lights, there's no algae, we have the odd tiny snail but the crab eats them when he sees them... We can't add any more fish until the problem clears up and I'm bored of these ones now! (I'm joking!)

Thanks

D x

What is the actual capacity of your tank? Which fish are in it? A week isn't particularly long for a cycle to take place, and for a cycle to effectively take place, ammonia has to be present, and that won't have happened in an empty tank. Have a quick look on these forums for "the nitrogen cycle".

 

[SkiFletch]

yeah, you're going through whats commonly refferred to as a "Cycle" around here. Dont believe the LFS, one week with no fish cannot build up your beneficial bacteria. The colonies are still growing and until they get large enough to process the ammonia your fish are producing via waste your water will be polluted. When doing a cycle with fish like you are it usually takes about 4 weeks for the bacteria to grow big enough colonies to support more fish. Make sure you do regular large water changes until then to keep the toxin levels down and go check out some of the stickies on cycling in this forum

Good luck