Lost a Threadfin Rainbow fish today :(

I have a 10 gallon tank that had red cherry shrimp and 5 Threadfin Rainbow fish, there are a lot of live plants too. Sadly today I lost a Threadfin, well he's going to die, he is just barely alive. I've had the tank over a month, do weekly water changes, but never actually tested the water, thinking I need to now. The fish was floating around the bottom, upside down, he'd swim but was on his side or upside down. I moved him to a container with some new water and some tank water, seemed to be getting a little better, but now he's almost dead He didn't look like anything was wrong except for the floating weird.

I really didn't know what to do, I couldn't leave to run and test my water to know what needed to be done but I plan to get my water tested tomorrow and then can decide what to do to help keep the others from dying. The shrimp and other fish seem totally fine. I did do about a 20% water change.

Does this speak to anyone about what might be wrong? Maybe Ammonia levels? My tank seems lately to be a little messier (had 4 ghost shrimp, 3 sold and one came out of hiding and then died) but the shrimp and one snail I see in there seem to be cleaning up things.

 

First, rainbows needs to be in a larger aquarium 40+.

most likely he is like that due to stress.

 

Yes indeed, rainbows need plenty of swimming space. My Easterns have 5 feet and use every inch of it.

Is your tank fully cycled? The fact you're going to get your water tested tomorrow suggests that you don't have a test kit. Get one while you're there. While they are not absolutely essential, they're pretty close to it. I'd put it up there with a net in terms of necessity . For the convenience as much as anything else, it's a worthwhile purchase.

Post the results here when you get it tested.

With that load, you should be changing 50%-75% of your water at least once per week.

 

I'm curious as to how you cycled this tank, given that you've never tested your water.

As mentioned above, consider getting the API master kit. It's what most of us use with great success.

Also, I agree that your water changes need beefing up, and you should have this stock in a larger tank, absolute minimum would be 20 gallons. This species actually requires more frequent water changes than many others. It demands pristine conditions.

 

I bought a tank that had been cycled for 3 months, the person who I got it from was going to use it then decided to go bigger. The Threadfin Rainbow fish are only about an inch and a half long, I believe they are some of the smallest rainbows. I do plan to get a test kit when I get my water tested. I haven't before because Petsmart does free water tests.

My rainbows have been doing well in this tank, not stressed, but displaying their fins and racing around, their colors have been great. From my research they're fine in this size tank, but then I've never had the chance to ask someone who really knows this specific fish as they are not that common in stores, only a specific Petsmart carries them up here that I've seen (and there are a lot of both the Petsmarts and Petcos) and the one big fish store doesn't even carry them. This fish can be a lot different than other species of rainbow fish, for one they are pretty small. I don't really have the ability to upgrade to a bigger tank, my landlord only allows this one 10 gallon, so should I just sell them?

 

If it were me, I'd rehome them. Your tank is not appropriate.

They get to about 2" max but, in this case, it's their behavior that warrants a larger tank, not their size. Kind of like with a rainbow shark. His size doesn't demand a 75 gallon tank, but his attitude sure does.

 

I used to teach at the university level, both undergrad and grad, and part of what I taught my students was that you have to look at a lot of resources before choosing what to follow. In the age of the Internet, it's even harder as plagiarism is out of control and misinformation gets repeated ad infinitum.

You will get a lot of very good info here from very experienced people of different backgrounds. They will at times disagree with each other, but that is also very important to read through because different sides can have valid points.

Basically, yes, your tank is overcrowded, and while the fish may be ok in there briefly as a quarantine tank, they will not thrive, and it's only a matter of time before they go downhill.

A 10-gal can comfortably house 1 Betta or 3-4 fancy male guppies or 5 neon tetras or 15 male Endler's. There are a few more kinds, but not many. It's not about their size alone--it's about their habits and water needs.

I once considered doing a 29-gal threadfin rainbow species tanks with a shoal of small cories but didn't do it because I have too many tanks. You could go down to 20-gal possibly, but that hampers their swimming style.

You can also go examine sites devoted entirely to Rainbowfish and look for the people who specialize in threadfins. It's a very good idea to look up scholarly articles and track down the university people who have been conducting research on them. My personal experience is that these researchers truly love the fish they work with and are rarely contacted by lay people, so they tend to be willing to answer questions.

 

I advertised my fish locally (because I don't know how to go about shipping if someone wanted them on here), I may not get more fish and just focus on the shrimp for now. Thank you everyone. I didn't even get a chance to go test my water, after work had my kids to feed, dogs to take care of, but I am ordering the API test kit on Amazon so I can keep up on water testing. I hope to sell the fish soon and not lose any before that. Thanks again. I'm sad about having to sell them, but they do deserve better.