Extremely clamped fins! HELP!

[MMK]

I haven't posted on here is forever, but I'm hoping to get assistance. I was gone for the weekend and came home today. Two of the bettas my divided tank have very bad clamped fins, but otherwise seen okay. The third doesn't look too bad. I have tested the water and it is fine. My room mate looked after my bettas and fed them. She is very good and I trust her completely not to over feed. She has been watching them for over a year when I leave on weekends. I saw them on Thursday night and all looked fine and this morning when I got back I found the very badly clamped fins.

I'm hesitant to do another water change because the Nitrates are SO low already. I was debating taking them all out and putting them in separate hospital tanks. Is this a good idea? Should I medicate?

It just so sudden, I don't know what to do! I've kept bettas for 3 years now in large cycled tanks with no problems!




Housing
What size is your tank? 15 gallons
What temperature is your tank? 80 degrees
Does your tank have a filter? Yes,
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes!
What tank mates does your betta fish live with? It is a 15 gallon, divided three ways. There are also small pond snails.

Food
What type of food do you feed your betta fish? Top Fin: Blood worms occasionally. Betta bites and betta buffet pellets.
How often do you feed your betta fish? They each get two pellets, twice a day. They are fasted once a week.

Maintenance
How often do you perform a water change? Once a week, every week.
What percentage of the water do you change when you perform a water change? About 20% change on a cycled tank.
What type of additives do you add to the water when you perform a water change? Nutra fin water conditioner and Flurish excel for the plants.

Water Parameters:
Have you tested your water? Ammonia is 0. Nitrites are 0. Nitrate are very low, below 5. The water is coloured, but lighter than the designation for 5ppm. PH is between 7.5-8.0, which is normal. Could the Nitrate cause a problem? I don't think so!

Symptoms and Treatment
How has your betta fish's appearance changed? Yes, two have extremely clamped fins. Ones are so clamped he appears to have trouble swimming. The third doesn't look too bad, maybe slightly clamped.
How has your betta fish's behavior changed? All are still interested in food and swim to the front of the tank. The one has trouble swimming the fins are so clamped. He rests on leaves are the bottom, unless I come to the top of the tank.
When did you start noticing the symptoms? Today.
Have you started treating your fish? No, I don't know what to do.
Does your fish have any history of being ill? No
How old is your fish (approximately)? One is very young, about 5 months. One is about a year and the last is about 1.5 years.

[MMK]

I just shot a few super quick photos to show everyone.


This is the tank. Everything is there has been for a while. The drift wood has been sanded down, it is not sharp.


This is the VT who is the worst. Although a VT, his fins are usually very large. They are SO clamped. Sorry it's blurry, I just took super fast photos.


The one on the right is the young SD/HM....he usually has very spread fins in comparison. He is the newest. Been in the tank about a week. Although, he was in a separate hospital tanks first for two weeks and was perfectly healthy. The one on the right in my HM, who is the oldest. His fins are the lest clamped.

[Oldfishlady]

Welcome back and sorry you are having problems.....when a fish has a sudden change like that-often its the environment....I would go ahead and make a 50% water change and dose the dechlorinator for the full volume of the tank for the next 2 days and see if that helps any....sometimes it can be contamination of some sorts and also double check your water temp with a separate thermometer and if you just made a water change and the water level went lower than the heater that could cause a crack-double check the heater and make sure you don't have a stray volt going through the tank.

Good luck and keep us posted.....

Wow...just saw the pics....beautiful....nice job.....

[MMK]

Thank you Oldfishlady.

I checked with another thermometer and the temperature is indeed 80. I looked over the thermometer and it appears as though it fell below the top line for the water level (not a fully submergible heater). I can't see any obvious cracks though and it is working. I can't feel or obviously tell if there is a stray volt. Is there another way to check?

The VT seems to be darting and hiding a bit more now too...the others seem otherwise fine.

I'll do the water change and cross my fingers! Thanks.

PS the last photo should say the SD/HM is on the LEFT. I just can't edit that post.