Discus Nitrates Catfish Help!

[joannr24]

Hello, I am new to this site and would really love some help.

I have a 55 gallon corner tank with 6 Otocinclus, 6 Juvenile Discus, 6 Glofish Danios, 2 Glassfish, 3 Kuhli Loaches and 1 Yo-Yo Loach. I am concerned with my Nitrates. The tank is fully cycled and I do two 25% water changes a week. I vacuum the gravel about twice a month.

My ammonia and nitrites are consistently 0, but I struggle with my nitrates. Typically they range between 10 and 20 ppm. I have a canister filter with sponges and biological media but because of the discus no carbon. The water is crystal clear and all fish are doing well except for the Oto's and the two BN Catfish I had who have recently passed away.

I bought seven Otos last weekend and have lost two. There is a lot of brown algae in the tank and the Otos are working on that but seem more obsessed with the glass which is pretty clean. Since I bought them on last Saturday two have died. Also, I had two bristlenose catfish and they died also. The BN's were in the tank for about two months. One died about a month ago and the other is dying this morning. Neither one of them grew. They were about 1" at death. The Discus are doing great, although some have grown huge and about two have stayed small. All of the discus eat the food. They are beggers and none are hiding and not eating.

I do not have live plants in the tank because they were a pain so I have several plastic plants. I also have a large airstone that keeps the tank aerated. The temperature typically runs around 84-85 degrees. My Ph is 7.4. I use a mixture of RO water and tap water, treated with Prime for my water changes.

I feed the fish one freshwater frenzy frozen cube in the morning, one small bloodworm cube at lunch, and one frozen cube of brine shrimp with spirulina for dinner. I melt the cube in a cup of aquarium water before I feed it and spread it through the tank. The food appears to be gone in about three minutes.

Any ideas on how to permanently lower the nitrates to below ten would be greatly appreciated.

Thanks

 

[minxfishy]

Your nitrates look fine to me, some of us have nitrates out of the tap at 20ppm so yours are nowhere near being a problem.

The bristles and the ottos would not really appreciate that temperature, I would say max of 80 for both, although the discus like it warmer the plecs and ottos like it cooler.

 

[Davo86]

Hey
might seem obvious but have you tested the tap water?

Also a nitrate reading of 10-20 is perfectly acceptable and shouldn't be the cause for the death of otos or a very hardy species like an ancistrus.
My only concern would be that the catfish may not be getting enough food? is there any bogwood in the tank? do you add any veggies such as courgette?

with ottos i wouldn't personally be prepared to go above 82F although i realise this i necessary for the discus

 

[kev_kb]

Discus juveniles shouldn't really be in a tank with gravel. Given the amount of food they need it would be much easier to maintain them in a bare bottom tank. You can keep them with gravel but it's a lot more work.

If I where you I'd vacuum the gravel at each water change. As you have brown algae your either feeding too much for the water changes your doing or the tank has too much light over it.

 

[rocknurworld2006]

what kind of lighting do u have on it?
do u have any sunlight onto the tank?
and how much do u feed and how often?