Tank overstocking

[Mattrich99]

Currently have a 225 gallon tank. It’s 6’L,20”w,3’T.
It’s currently being occupied by a 9” copper red Oscar, 10-11” albino chili Oscar, 20” ornate bichir, and a 22” clown knife. Currently trying to rehome the clown knife.

My problem and question is the clown knife stresses out the Oscar’s a ton. I have 4 more albino tiger Oscar’s 10”+.

Should I add the other 4 Oscar’s to reduce aggression? Filtration is not an issue. I can add more as necessary.

Attached is the current tank

 

[tlindsey]

Should I add the other 4 Oscar’s to reduce aggression

Welcome aboard.
No it will make things worse. Rehome the Clown knife.

 

[wednesday13]

Looks like the CK is taking a good beating and the oscars are un touched. Id ditch the oscars Lol… nice size ornate

 

[tlindsey]

Looks like the CK is taking a good beating and the oscars are un touched.

I didn't notice the tail of the CK but Oscar’s don't normally stay at the surface like that from my experience with them. Ornate bichir can be territorial aswell. Yes agree rehome either one.

 

[skjl47]

Filtration is not an issue. I can add more as necessary.

Hello; Let me address a touchy topic. It would be nice if extra filtration was the cure for overstocking in terms of water conditions. Assuming the tank is stable with regard to ammonia & nitrites, such would indicate you have enough biological filtration in place (the beneficial bacteria known as BB).

The rest of the filtration is mechanical and is polishing the water so to speak. Adding more power filtration does little with regard to water quality. Maybe helps keep oxygen levels stable by surface agitation. Feel free to rebut. You will join the many who feel I am wrong about this.

Hello; The snapshot of the tank illustrates something I have seen often. The Oscars are low in the pecking order (dormancy) of the tank. The knifefish likely is the top dog. The Oscars are as far away in a top corner as they can get. The other bottom fish has enough spunk to claim a bottom portion, but not easily. A stressed tank. Likely stress hormones also affect water quality.

Hello; You did not mention water parameters from tests. If ammonia & nitrites are zero such is a good start. I will make a wild & unsupported, so far, guess that the nitrates are some high. Would be interesting to know the water change volume & frequency, but such might derail the thread.

My personal take is the tank stocked with a problematic set of species. It is a big tank but still too small for the fish selected. My guess is keeping the Oscars or the knifefish but not both in the same tank. Do not add more fish.

I was in an area shop some years ago. had a tank full of kribensis cichlids. I was talking to the shop owner and remarked that when I raised kribensis the males did not tolerate each other so well. He thought it was the crowding that kept territorial aggression down.

But good luck whatever you do.

 

[skjl47]

The Oscars are low in the pecking order (dormancy) of the tank.

Hello; I meant to write dominance rather than dormancy.

 

[LBDave]

Back in the day, when I was a kid, I had a clown knife with an oscar. NOT GOOD. Big chunks taken out of oscar's fins.
Clown knife was returned to LFS.

 

[Mattrich99]

Looks like the CK is taking a good beating and the oscars are un touched. Id ditch the oscars Lol… nice size ornate

The ck got his nose a little beat up in transport and the fin rot was from the previous owner lacking on water quality while he was trying to sell. Ck is healing up nicely with the medicine. Lots of improvements this last week. I’m removing ck from the tank today and he’ll have his own space.

 

[Mattrich99]

Hello; Let me address a touchy topic. It would be nice if extra filtration was the cure for overstocking in terms of water conditions. Assuming the tank is stable with regard to ammonia & nitrites, such would indicate you have enough biological filtration in place (the beneficial bacteria known as BB).

The rest of the filtration is mechanical and is polishing the water so to speak. Adding more power filtration does little with regard to water quality. Maybe helps keep oxygen levels stable by surface agitation. Feel free to rebut. You will join the many who feel I am wrong about this.

Hello; The snapshot of the tank illustrates something I have seen often. The Oscars are low in the pecking order (dormancy) of the tank. The knifefish likely is the top dog. The Oscars are as far away in a top corner as they can get. The other bottom fish has enough spunk to claim a bottom portion, but not easily. A stressed tank. Likely stress hormones also affect water quality.

Hello; You did not mention water parameters from tests. If ammonia & nitrites are zero such is a good start. I will make a wild & unsupported, so far, guess that the nitrates are some high. Would be interesting to know the water change volume & frequency, but such might derail the thread.

My personal take is the tank stocked with a problematic set of species. It is a big tank but still too small for the fish selected. My guess is keeping the Oscars or the knifefish but not both in the same tank. Do not add more fish.

I was in an area shop some years ago. had a tank full of kribensis cichlids. I was talking to the shop owner and remarked that when I raised kribensis the males did not tolerate each other so well. He thought it was the crowding that kept territorial aggression down.

But good luck whatever you do.

 

[Mattrich99]

About 1-2ppm nitrate, 0 nitrite, 0 ammonia, and a 7.4 ph. Clown knife is getting his own space today. I’ve been doing a 25% water change weekly. Adding beneficial bacteria treatments and bacterial infection medicine as well. I bought the tank with the bichir and the clown knife was supposed to go to someone else. The other buyer fell through for CK and I took him in for free since the previous owner did not have a tank for him. I never planned on having ck so I’m just trying to figure it out. The plan is to get Ck fins healed up and rehome.