Can't figure out why my rasboras are dying

[dereks]

29 GALLON planted

Never seen fish die off like this, especially without symptoms.

No ammonia. 20 nitrates I think, can't remember specifically but it wasn't alarming. Same with nitrates.

25% WCs once per week.

The tank has been up for 14 years without any recent problems.

The only thing I can think is the angelfish I just bought had something he passed onto them. But the guppies, Corey cats, yoyos, betta fish, and bamboo shrimp all seem ok.

Harlequin Rasboras are 2-3 years old, I pulled out 3 today, 1 yesterday, 1 the day before. 3-4 in the past 2-3 weeks. Seems to be accelerating.

Thoughts?

 

[DefJ123]

A friend of mine had similar in a 20g planted. Had shrimp, snails, a sucker and merah rasboras. Within couple weeks 14 merah rasboras died, nothing else in the tank was bothered. Colony of shrimp was fine, snails fine, the sucker (similar to hillstream loach, cant remember exactly) fine. Very odd indeed.

Unfortunately we couldnt figure out what happened. I find it interesting its Rasboras again though. Following just to see what others say. Sorry I cant be of more help...

 

[dereks]

*Same with nitrItes.

 

[fishorama]

Yeah, it could be something the angel brought in. Does it or rasboras show anything like white or red patches or streaks? Bloated abdomen? Eating ok? Nipped fins?

When in doubt, change more water! How big are your yoyos? Your stocking seems, well, less than optimal & on the heavy side for a 29g...I know you're not a newb, but how big & how many of each species do you have? I'm kind of surprised you haven't had issues with some of those fish choices, but rasboras would have been my least to be concerned about.

I agree, it sounds like some disease, parasite or other pathogen. I have no guess, sorry.

 

[dereks]

Man, I haven't noticed ANYTHING out of the ordinary, appearance, behavior, eating, etc.

2 small yoyos, they've been in there for 3 years, I swear I haven't noticed them grow a millimeter.

So those ^^ +1 betta, 1 guppy, 2 shrimp, 3 Corey cats, plus one tiny angel. I think that's it. I mean I'm down to 2 rasboras.

If they were full grown I'd call that aquarium over stocked, but right now it's just got a bunch of real small fish in it, I'm able to get away with very minimal amounts of food, still allowing all the fish to eat.

 

[fishorama]

I wonder why your yoyos haven't grown in 3 years! I'd suspect internal parasites, loaches are prone to them often. I like to treat them in QT with flubendazole or levamisole just to be sure. They should be 4-6 inches by now, somethings wrong there.

But the rasboras deaths are likely linked to the new angel. I don't know what it may be but after 3 years they had to have gotten something new or been weakened in some way to make them susceptible to something already in the tank.

Sorry, mystery deaths with no signs are almost impossible to ID.

 

[tanker]

What is your Nitrite again?? Is it only the Rasboras??

 

[dereks]

I wonder why your yoyos haven't grown in 3 years! I'd suspect internal parasites, loaches are prone to them often. I like to treat them in QT with flubendazole or levamisole just to be sure. They should be 4-6 inches by now, somethings wrong there.

But the rasboras deaths are likely linked to the new angel. I don't know what it may be but after 3 years they had to have gotten something new or been weakened in some way to make them susceptible to something already in the tank.

Sorry, mystery deaths with no signs are almost impossible to ID.

My understanding is that yoyos are slow growers, I'm only saying they grow slowly enough to where I don't notice the growth at all. Sure it could be something wrong, but if so, they survived it for 3 years. The problem seems isolated to the harlequin.

What is your Nitrite again?? Is it only the Rasboras??

I forget what the reading was, I'm not familiar with testing, this is the first time I've tested in years. I do know it fell within the acceptable range, there were no red flags on the test. This evening I can retest.

 

[DefJ123]

The only acceptable nitrITE reading is 0 ppm.

 

[FreshyFresh]

I too would say the introduction of the angel fish brought something into the tank the rasboras couldn't handle. Not an uncommon occurrence.

I had a weird experience with harlequin rasboras a few years ago. Petsmart had them on sale for $1/ea and. They were tiny. I bought 8 of them to start off in my well established, planted 10g that had red cherry shrimp, snails and a few celestial pearl danios. Over the course of a week, every one of them died.