Dwarf Gourami Killing Other Fish?

I bought my male Dwarf Gourami 6 months ago and the pet store reassured me he was passive. Even saying he was extremely passive. He was fine with the other fish at first but he would wake me during the night thrashing the tank themometor. I couldn't figure out how he was doing it I just knew he was. About 2 months after getting him I got a bottom-sucker and within 24 hours one of my fish died and the rest followed each within 24 hours till all were gone (including bottom-sucker) leaving only the Gourami. I thought it might have been due to the filter so I waited a while before I bought anymore fish. About 2 months ago I ourchased some more (all passive-according to the pet store) and the same exact thing happened. It starts 24 hours after I've put them all in together and then they all die, one by one, within 24 hours of each other and they don't float to the top so I know they must have been killed close to the bottom or the filter system wouldn't have picked them up. The bottom feeders sink to the bottom leaving only the Gourami left. I have a 15 gallon tank and am convinced and confused that my Gourami would feel the need to kill them. He doesn't thrash the themometor anymore but I know that is how he must be killing them. It's too similar to be just coincidenous.Can this truly be possible? And if so then why wasn't I warned? r do I just have a psycho fish-LOL?

 

Generally, it has been my experience that dwarf gouramis are peaceful and are good in community tanks. It sounds like you may a psycho fish - maybe a product of too much inbreeding by the breeders. Have you tried getting another dwarf gourami or two? That may help his behavior, then again it may not. It sounds like you have a crazy fish.

 

My Dwarf Gourami sometimes gets a little territorial. Not too much tho!

 

We have a psycho dwarf gourami too - if we go near the tank his fins bristle up and he goes mad and he killed the other fish in the tank with him, so now he lives with an otocinclus and a pleco who he tolerates but you can tell he doesn't like them (they have good hiding places too). Maybe it is inbreeding, or as one of my friends said, lack of space? We're gonna try him in a whole herd of gouramis when we set up our new tank.

 

my golden gourami is crazy he is sumtimes is very territorial but my dwarf red fire just swims away from him when hes in a bad mood they r gettin on better now and swim about together the guppies I have are also crazy characters they take no s**t from the golden gourami I actually think there puttin him in his place lol!!!

 

that is possible that he is killing him but unlikely because they are a peaceful fish

 

I've had a similar problem, and I wouldn't recommend adding another gourami with that "psycho fish". One of my dwarf gouramis constantly picks on the other, chasing it around, leaving the harassed fish constantly alert and on the look out, with his fins up.

 

If you want to keep that fish I would not put another in with it. I would get a small tank and have it in there by itself. Why put other fish in and take a chance at giving them a death sentence??

Rose

 

The main reason if one is picking on another if you have two is that they are both males and they fight, but u have a psyco fish mate

 

Have you considered putting a snail or something in there with a shell that he couldn't kill? It may teach him a lesson that not everything can be killed. My fish tried to peck at their snails (one or two times) and after bouncing off of them like they had been rubber balls they soon learned not to tangle with them.

Rose

 

So I just got a dwarf gourami. I think he is so beautiful but Huston, I think we may have a problem! Do you think he could be killing my other fish?! I see him chasing them if they get within 4 inches of him. I am new to planted aquariums so here is the info about my tank.

Cycled for 2 months. Current parameters Ammonia 0 Nitrite 0 Nitrate 0.

55 gallon tank Aquaclear HOB, air stone, temp 80 degrees

1 Dwarf Gourami

6 baby corydora - 2 died so now 4 corys

10 neon tetra - 6 died now 4 tetra

6 platties - 1 died now 5 platties

4 Amano Shrimp- all alive and hiding

I didn’t know if it was the water parameters so I did a 25% water change. I add Flourish Excel every few days for the plants. I have only had him for 3 days and this is what happened. All of the fish are pretty new to the tank... Added platties first for a week, then corys then the neons and gourami. They don’t slowly die, they just boom. Dead. I feed algae wafers, Omega flake food, blood worms or frozen shrimp. Help! What am I doing wrong?! Or is he just a killer?

 

It could potentially be the dwarf, as they can be pretty aggressive. It is a bit strange one would be aggressive in a 55 gallon, though. Neons enjoy a well established tank I believe, and platies are know for having poor immune systems and genetics, so it could just be that.

 

Cycled for 2 months. Current parameters Ammonia 0 Nitrite 0 Nitrate 0.

0 Nitrate? What are you using to test?

If you have 0 Nitrate, your tank isn’t cycled.

 

0 Nitrate? What are you using to test?

If you have 0 Nitrate, your tank isn’t cycled.

It’s zero because after I cycled it, I did a 98% water change to get the nitrates down again before adding fish. Before adding fish it was 160 and deep red

It’s zero because after I cycled it, I did a 98% water change to get the nitrates down again before adding fish. Before adding fish it was 160 and deep red

My tap water is 0, 0, 0

 

It’s zero because after I cycled it, I did a 98% water change to get the nitrates down again before adding fish. Before adding fish it was 160 and deep red

According to your first post, you added fish at least a week ago. When did you test and get a 0 nitrate result?

 

I agree that although it is a possibility, other explanations seem more likely.

Did you quarantine any of these fish?

 

According to your first post, you added fish at least a week ago. When did you test and get a 0 nitrate result?

A few weeks ago it was
Ammonia 0, nitrite 0. Nitrate 160s
So I did a huge water change and it then read ammonia 0, nitrite 0, and nitrate 0. Then I added some ammonia and everything seemed good still the next day so I added fish.
Parameters haven’t changed in 2 weeks since adding fish.

 

What are you using to test your water parameters?

 

Could be the gourami, the Excel, or just weak fish. Being all the fish are new, I suspect number 3. When adding new fish, especially small schooling species, I always try to recommend getting a few more than what you're planning, to compensate for the likely die-offs within the first week.

 

What are you using to test your water parameters?

API Master Kit

I agree that although it is a possibility, other explanations seem more likely.

Did you quarantine any of these fish?

No I didn’t quarantine any of them

According to your first post, you added fish at least a week ago. When did you test and get a 0 nitrate result?

It’s been zero nitrates since I did the large water change. Then added the platies nitrates 0, 1 week after platies nitrate 0, then added Corydoras for 3 days and nitrates still 0, and now added the neons and dwarf gourami for the last 3 days all zeros still. Maybe since I have plants?

I try to keep it bEtween 78 and 80 degrees. But I came home from work and the temp was 82 so I turned it down. Do you guys think that could have caused the mass casualties?

 

I try to keep it bEtween 78 and 80 degrees. But I came home from work and the temp was 82 so I turned it down. Do you guys think that could have caused the mass casualties?

No.

 

I try to keep it bEtween 78 and 80 degrees. But I came home from work and the temp was 82 so I turned it down. Do you guys think that could have caused the mass casualties?

Not likely. Temp changes have to be pretty drastic IME.

What cories are they? Some need much cooler water, and so do platies. Id bring it steadily down to 75-77 range.


The API test, are you shaking the living day lights out of that bottle?

 

The corys I have are julI and 1 that looks like a julI but starts w an S and has some orange color on the fins.
Ok I will turn down the heat.
I will also redo the tests right now and shake shake shake those bottles.

Not likely. Temp changes have to be pretty drastic IME.

What cories are they? Some need much cooler water, and so do platies. Id bring it steadily down to 75-77 range.


The API test, are you shaking the living day lights out of that bottle?

Ok since shaking the bottle until my arm was going to fall off... looks like 5.0 nitrates.

 

Okay good, good parameters then.

Nitrate from the API kit can be a pain as you gotta shake the heck out of it for the most accurate reading. I'm thinking this was behind your super high reading and then your zero readings.

 

That ph is 8.3 and very alkaline. I live in the desert . Think that may be the reason for the deaths? Trying hard to rule out everything before returning this little spunk fish.

 

That ph is 8.3 and very alkaline. I live in the desert . Think that may be the reason for the deaths? Trying hard to rule out everything before returning this little spunk fish.

If you bought them from your local store, they probably have similar water hardness (I know mine does).
While your water is quite high, if the fish were fine with it before, its unlikely.

BUT, you could always test the water in the bag when you buy the fish to see if there was a difference.

How did you acclimate the fish to your tank when you bought them?

 

If you bought them from your local store, they probably have similar water hardness (I know mine does).
While your water is quite high, if the fish were fine with it before, its unlikely.

BUT, you could always test the water in the bag when you buy the fish to see if there was a difference.

How did you acclimate the fish to your tank when you bought them?

That’s a great idea! I will test the water or simply ask what their ph is. I put the bag in the water for about 20 min then added around 3 oz of my tank water every few min until the bag was full. Then I scooped them out and put them in the tank so I wouldn’t get any of their water into my tank water. Should I do it differently?

 

That’s a great idea! I will test the water or simply ask what their ph is. I put the bag in the water for about 20 min then added around 3 oz of my tank water every few min until the bag was full. Then I scooped them out and put them in the tank so I wouldn’t get any of their water into my tank water. Should I do it differently?

You did just fine with acclimating, I don't think it was how you did it that killed them. For more sensitive species in the future you could do less water added over a longer period of time, but otherwise I see nothing wrong with how you did it.

 

Update: I don’t think he is killing them. Pretty sure it’s just new fish not liking the change in ph I’ll have to try to acclimate to ph longer next batch of fish.