helping betta fish recover from fin rot

[corvina]

I've got a 5 gal betta tank with my daughter's two fish, and we've been keeping the water condition top-notch. The tank's got a filter and heater, and the ammonia and nitrate levels are at 0, with nitrate at 5. Recently, my daughter noticed her betta's tail looked a bit ragged, but the other fish seemed fine. We figured it might've been stress from our trip out of town - she fed them a bit extra before we left, then they didn't eat for two days, and got extra food when we got back.

We took the betta out and put him in a small 1gal bowl with a heater but no filter, added 1 tsp aquarium salt, and changed the water every day. It's been 8 days now, and his tail's looking much better. Meanwhile, we did a vacuum, rinsed all the stuff in the tank with hot water, and did a 75% water change for the other fish. He's still in the 5 gal tank, and he's doing just fine.

So, I'm wondering what to do next. Should we put the betta back in the 5 gal tank? Will switching from salty water every day to no salt cause any issues? Will his tail keep healing and growing? I've included some pics of his tail today.

[Rizen]

I want to address something before anyone else jumps in - it's generally not a good idea to keep two bettas together, especially males. There's a lot of debate about the minimum tank size, but let's focus on the issue at hand.

My first thought is that the fin rot could be caused by stress from being housed with another male. Even if the divider isn't see-through, fish can detect hormones released by other fish. I strongly think you should consider getting another 5-gallon tank and housing the bettas separately. This will give them both the space they need to be happy and healthy, and reduce their stress levels. Stress is a major cause of death in fish, but it's usually preventable.

Another possible cause of fin tearing is when they get caught on artificial decorations. However, your tank doesn't appear to have any decorations that could be causing this, so that might not be the issue. I'd recommend adding some plants or decorations that your fish can hide in or around. This will give them a sense of security and a place to hide if they feel threatened. Just make sure to avoid plastic plants, as they can cause more fin damage.

Regarding the switch from saltwater to freshwater, I don't think it will be fatal as long as you acclimate him properly. However, I do think it's a good idea to look into getting another tank. Good luck, and keep us updated on any changes.

[corvina]

I appreciate your input. I had initially expressed concerns about getting another betta, but my daughter was quite keen on it. The fish have cohabited for about six months now. The separator is dark, so they can't see each other. The sick betta is really calm and never displays his fins, even when I use a mirror. On the other hand, the other betta is quite high-strung and always showing off his fins to various things. In their home tank, each of them has two artificial plants for hiding, and we also have a nerite snail that helps with algae control. We periodically switch the snail between sides to keep the tank clean. We haven't had any issues in the past six months, but I know a bigger tank is always better. Would you recommend separating them, even if it's just a 3-gallon tank with a filter and heater? Is it possible for fin rot to develop after six months of peaceful coexistence? The picture shows our makeshift emergency tank, which we've kept bare for easy daily water changes. Thanks again for your help.

[Rizen]

I've got a 5 gal betta tank with my daughter's two fish, and we've been keeping the water condition top-notch. The tank's got a filter and heater, and the ammonia and nitrate levels are at 0, with nitrate at 5. Recently, my daughter noticed her betta's tail looked a bit ragged, but the other fish seemed fine. We figured it might've been stress from our trip out of town - she fed them a bit extra before we left, then they didn't eat for two days, and got extra food when we got back.

We took the betta out and put him in a small 1gal bowl with a heater but no filter, added 1 tsp aquarium salt, and changed the water every day. It's been 8 days now, and his tail's looking much better. Meanwhile, we did a vacuum, rinsed all the stuff in the tank with hot water, and did a 75% water change for the other fish. He's still in the 5 gal tank, and he's doing just fine.

So, I'm wondering what to do next. Should we put the betta back in the 5 gal tank? Will switching from salty water every day to no salt cause any issues? Will his tail keep healing and growing? I've included some pics of his tail today.

I can see why you'd use an empty emergency tank - it's definitely easier to change the water every day. When it comes to minimum tank size, there's a lot of debate, and I don't think my opinion is the only one that matters. For me, personally, I wouldn't put a betta in anything less than 5 gallons long-term. A 2.5 gallon is the absolute minimum, but most people in the hobby think bigger is better. My betta is in a 10-gallon tank, for example.

A 3-gallon tank would be an improvement over the 2.5-gallon split you've got now, but I think a 5-gallon tank would be more fun to decorate. It's also better for the fish, in my opinion.

Your fish's personalities do sound like they could be a problem, though. I've only been keeping betta for a little while, so I'm not an expert, but it seems to me that your two fish have very different temperaments. Even if it's just to another 2.5-gallon tank, I'd separate them as soon as it's safe to do so. If you do get a 5-gallon tank or more, don't forget to cycle the water - it's really important for the fish.

I'm not sure what could have caused the fin rot to start after six months, unless something changed that stressed him out.

[juicebox]

I'm curious about your water change routine - how often did you do them and what percentage of the water did you change each time? Poor water quality is usually the culprit behind fin rot, so I'm wondering if that might've played a role here.