Am I overcrowding my planted tank?

[J Migidy]

I have a 55 gallon rectangular planted tank with 3 inches of subtrate and 2 Penguin 350 bio wheels. The only big fish I have is a 6inch clown pleco that I've had for 3 years. I have a 4inch ghost knife fish, six 2inch zebra danios, and six quarter size angelfish. That's 14 fish all together. I test the water twice a week for ammonia, ph, nitrite and nitrate. The only thing that does not come up zero is my nitrate levels. I show a little bit of that but not enough to get me worried. My tank does seem a litle full though and I'm worried about my angels. Will I have problems when they get bigger or am I ok no matter what?

 

[rich311k]

The Knife fish will get to large eventually and 6 adult angels will be pushing it. Chances are with 6 you will get at least one pair out of the fish. Once that happens they will become aggressive towards the rest and you will probably have to find new homes for some of your angels. For the moment your tank seems to be stocked fine just be prepared to make adjustments in 4 -6 months.

 

[evercl92]

You're not going to be able to get nitrates to 0. Even established aquariums shouldn't get that low. Just keep it on the low, and you'll be fine. I shoot for 20-40 ppm of nitrate in my tank, but it's heavily planted.

 

[Jchillin]

Are you worried about overstocking with the fish? See Rich's response.

In regard to nitrate levels, this is not a concern unless you bottom out or cannot maintain at least 5ppm on a daily basis. With a heavily planted tank, you may need to supplement nitrate. I am one of those who must.

 

[J Migidy]

The Knife fish will get to large eventually and 6 adult angels will be pushing it. Chances are with 6 you will get at least one pair out of the fish. For the moment your tank seems to be stocked fine just be prepared to make adjustments in 4 -6 months.

So does this mean that out of six angels I'll be left with a pair or if I'm lucky two pair? How about the knife fish? Will it outgrow the tank? If so what is the recommended size for a full grown knife fish?

 

[rich311k]

Yes you will almost certainly wind up with a mated pair maybe two. Two pairs in a 55 will probably not work but you might get lucky. Once they pair off and get in the mood they will harass the others relentlessly. Don't worry, they will be good size and will be a great centerpeice fish for years. I love mine.

The knife would be happy in a 75 gallon or more. There are a few threads in the general FW forum about this. Some very good reading.