Am I overloaded?

[Sasquatch]

Just a some questions about our aquarium in the hopes that it's nothing and, if not, getting ahead of any problems.

As mentionned, I have a 10g tank with 5 platies and a small catfish. We do regular water changes and check the water chemistry every week. Our pH is around 7.8-8.0, hardness around 120/70 (GH/KH). It's also a pretty heavily planted with around 20 stems of Hygrophila actively growing.

When we check the water quality we, of course, do ammonia and nitrites. The are always below the lowest level on the test charts (0.6 for ammonia, 0.1 for nitrites) but there is always a little color.

Is this normal (the very slight coloration) and if not, is it indicative of an overloaded tank?

Also, we have recently had a rise in our nitrates. They were fairly stable at 5-10ppm, but since we've added the catfish it's on a steady rise and was 20ppm this morning before I did the water change.

Could this also be a symptom of an overloaded tank?

We've recently upped the water changes to twice a week (20-25% each time) and are cutting back on the feedings. Admitedly, we were feeding more than usual since we have a pregnant platy, but with this water chemistry, we have cut back.

The behaviour of the fish is normal, except maybe the catfish who spends a lot of time swimming circles around the front of the tank. But that's only when he gets spooked (lights on/off, feeding).

Thanks for any advice.

[Chrona]

How big is the catfish? It sounds like the plants were balancing out the fish waste before. Also, how long ago did you add the catfish? The small amount of ammonia/nitrite may be a mini-spike, though I would think that the plants would absorb that little amount of ammonia if they are actively growing.

[Lady Hobbs]

You should not have ammonia or nitrites at all. I have a sneaky feeling that you may be overfeeding which is constantly keeping the ammonia levels up from the rotting food which is also turning into nitrites then.

Cut WAY back on feeding to every 2 to 3 days until you get these levels to come to 0.

[Sasquatch]

It's a small catfish, about 2.5"-3" long, and it'll stay that size, so no worries about it growing any larger. The catfish has been in there for about 3-4 weeks.

We've been getting these "background" levels of ammonia and nitrites since we added the most recent batch of platies. We added them mid-January and the catfish in early Febuary.

It could be that the tank is going through a mini cycle, it's been through a lot of changes in the last two months. We've added 4 fish (3 platies and 1 catfish), re-arranged the plants and went from 1tsp\gal salt to freshwater (we were treating diseases on a batch of swordtails, who all died anyway).

I have a sneaky feeling that you may be overfeeding which is constantly keeping the ammonia levels up from the rotting food which is also turning into nitrites then.

We'd thought of that too. I mentioned that we were feeding a lot because of the pregnant female. We've cut back recently, so hopefully it should improve. If not, maybe we'll cut back even more, though our catfish is already having trouble getting to his food 'cause the platies jump on it before it's gets to the bottom of the tank and\or before he can find it.

[Lady Hobbs]

You most likely killed off your bioload when you added the meds and then here come new fish so that mini-cycle sounds about right to me, as well. Just do small water changes to keep those guys alive and watch your readings.

[Severus]

Sounds like you have your situation figured out. You are not overloaded as far as bioload goes, it was proabably the feeding. Good luck with everything and let us know how your situation goes