Need info on african brown knife, ASAP

[Talvari]

So heres the issue... Ive had my 55 gallon tank running for more than a year, almost a year and a half. Its a semi aggressive tank. I started off with 6 tiger barbs, two gouramis, a hifin pleco, and adopted two clown loaches.

I moved back in May and one of the gouramis did not survive the move.

I recently redid my tank (four months back?) to black sand/eco complete, have live plants, added a few pieces of driftwood for my pleco, and added an African Brown Knife.

I lost power, tank temp dropped, my tank got ick. It cleared up within four weeks, but I lost both my clown loaches.

I replaced the loaches with rainbowfish, knowing that the loaches would have gotten too big for my tank.

About four/five weeks ago, I added two bristlenose pleco to grow out for my 46 gallon planted tank.

In the past two weeks, I have had five fish die. Two rainbows, two tiger barbs, and my gold gourami (who was around 5 inches long). The ammonia reading is 0. Nitrite, 0. Nitrate, 5. I do water changes every 7-10 days, and take out about half of the water. The fish are showing no signs of illness.

Someone proposed to me that it could be my African Brown Knife going after the fish at night. How likely is this???

 

[LyndaB]

I would say that it is most likely the brown knife. Although they are not listed as particularly aggressive, there is the warning not to keep them with smaller fish. Many people report the knife stalking their other fish.

I watched my gold gouramis kill each other off. Started with 3, ended up with 1, in a very short period of time.

Tiger barbs are highly aggressive and it is recommended to have a larger school of them to lessen the aggression somewhat. Again, I watched my tigers beat each other to death.

You have a couple of options as to who the culprit might be, if indeed there is one.

 

[Talvari]

Sorry, forgot to add that I only had one gourami at the moment. The other one never survived the move several months back. The gold gourami couldnt have been the one killing the other fish because he died.

My tiger barbs chased each other, but never the other fish. They stay more towards the middle and the only time they really got aggressive was then it was feeding time. At any rate, usually it was the dominant male of the group fighting with the less dominant male. He usually ignored the girls, or at the very least, shimmied up to them and rubbed himself against them.

I lost the two Australians first, then went the Gourami, then this morning I woke up to two of my *female* tiger barbs dead.

 

[Talvari]

Another thing Im confused about is... If it is a fish that is killing everyone else... Why are there no bites out of fins, no missing body parts, and the dead fish is whole and has no wounds on it?

Im not trying to be contradictory, I'm just trying to understand why these guys are dying. I'm in full panic mode, because I used the drippings from *this* tank to cycle my 46 gallon tank... And if its a disease, I dont want cross contamination!

 

[LyndaB]

When was the last time you introduced a new fish to this tank?

 

[Talvari]

Two bristle nose plecos about a month ago. Im growing them out a bit for my 46 gallon tank.

 

[LyndaB]

Another thing Im confused about is... If it is a fish that is killing everyone else... Why are there no bites out of fins, no missing body parts, and the dead fish is whole and has no wounds on it?

An aggressive fish can stress another fish to death, quite literally. There wouldn't necessarily be any marks or bites on the dead fish.

If you've been seeing deaths for 2 weeks and you put the BNs in there 4 weeks ago, it's possible they introduced something to your tank.

 

[ashleynicole]

Definitely sounds like something is going on. There are so many bacterial, viral and parasitic infections and some may show no visible signs.

I will be straight up, I don't like meds and prefer water changes to maintain health. however I was doing daily 50% water changes and still randomly losing fish for about a week. I finally got some parasite tabs made by jungle and they have metronidazole in them which is a decent antibiotic and treated all my tanks. It has been 4 months and I have not had one single death since then.

It was a long shot but it did the trick. I will never add another fish to my tank without quarentine for a minimum of two weeks ever again.

 

[Talvari]

I dont have a QT set up atm, but I brought these two home from were I work. Its probably not too much comfort, but we had them in store for about a week and a half and noone was showing any signs of illness for the duration of that time, or the time since.

Is there anything I should look for if it is some sort of illness? Ive probably said this too often but... Everyone has been eating. No spots. No strange worms. Coloration is fine. No clamped fins.

ETA: The two bristlenose are fine, too. They are always hanging around on the glass. The've grown a little in the past couple weeks. My hi-fin pleco is fine too, though he only comes out at night.

 

[Talvari]

Stupid Question: If the knife isnt getting enough to eat, that would probably stress him out enough to attack the other fish, right?

The only reason I ask is because I ran low on bloodworms and havent been able to pick up more. He eats the flakes just fin, but he used to GORGE on the bloodworms, and obviously I havent been able to do that as often.

 

[Talvari]

DARN IT!

I need to get rid of that knife. Seriously. Out of curiosity, I turned off all the lights in the kitchen/dining room, closed the blinds, turned off the lights in the tank... And watched my knife ram the heck out of my largest Rainbow. Twice.

Gah, I just dont know what to do with him. Ive got to go to work in a couple of hours and the only place that will take back fish in at least a half an our drive there and back. My other fish tank isnt fish ready yet!

 

[LyndaB]

Can you put any type of divider in the tank for now?

 

[LyndaB]

Stupid Question: If the knife isnt getting enough to eat, that would probably stress him out enough to attack the other fish, right?

There is no such thing as a stupid question.....

That said, what you're seeing seems to be typical behavior for the knife. Not much you can do if it's just doing what he's supposed to do.

 

[Talvari]

No, I dont have one. Im thinking about just moving the barbs and the rainwbows over to the 46 gallon for now. Its cycled and it has a light and a heater.. It just doesnt have much in the way of decorations. Or a lid.

The not having a lid is the main reason I didnt want to put the knife in there.

 

[Big-j]

I was pretty sure they were aggressive after dark, I'm glad you found the culprit, knifes are really cool fish but can be tough to live with in some situations, I'm sure your fish will be better off now

 

[Talvari]

Alright, I gave the knife to a friend of mine who has a 120 gallon African Cichlid tank. Hopefully with more space and more hiding spots, he'll do alot better.

I REALLY hope this means Ill stop losing fish...

 

[Talvari]

Well, its been more than 10 days and I have not lost a single fish. I think that means Im probably safe.

Only problem is now I have 3 tiger barbs who hide all the time and my husband does not want anymore. I think Im going to have to rehome them and start fresh with just the Rainbows and BNP.

I probably couldn't do Angelfish with Australian Rainbowfish, could I?

 

[Sharkbait54]

Sure you could.

 

[absolutangel04]

IMO, angels would be fine with bnp and Australian rainbow fish.

 

[Talvari]

I think Im settled on my new stocking lists. I rearranged them a little so all of the fish would work together. I figure with the amount of space on the bottom of the 55 gallon, the rams and corys should be OK together. Thoughts?

55 Gallon tank:

2 Bolivian Rams
2 Bristlenose Pleco
5 Australiain Rainbowfish
5 Peppered Cory Cats
10 Serpae Tetra

For my 46 gallon...

1 Bristlnose Pleco
12 Black Neon Tetra
12 Cardinal Tetra
1 Angelfish