I have a 5g tank, heater and filter. Is this fin rot, clamping or something else? If so what should I do? I have already changed the water about 80% and added bettafix. I have 2 coreydoras as well, so salts are not an option. He has been hiding inside a cave frequently, which is unusual for him. Help is much appreciated, I am a noob here.
What size is your tank? 5 gallons
What temperature is your tank? 76 - 78 F
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? 2 coreydoras (they get along quite well)
What type of food do you feed your betta fish? nutrafin max flakes
How often do you feed your betta fish? twice daily, though I fast him on saturdays
How often do you perform a water change? twice weekly
What percentage of the water do you change when you perform a water change? 25 - 50% (depending on cloudiness)
What type of additives do you add to the water when you perform a water change? aquaplus water conditioner (mixed in before water is added)
Have you tested your water? If so, what are the following parameters?
Ammonia: <0.25 ppm
Alkalinity: n/a (I will buy all these test kits asap!)
Symptoms and Treatment
How has your betta fish's appearance changed? his fins used to be expansive and have now shrank in width, as you will see in the picture.
How has your betta fish's behavior changed? he is hiding inside a little cave and only seems to resurface for air (though when he does, he appears energetic)
When did you start noticing the symptoms? last night (I was away for a night and when I came back, I noticed the fins and strange behaviour)
Have you started treating your fish? If so, how? 2.5 tsp bettafix (followed directions) as well as a 80% water change
Does your fish have any history of being ill?
How old is your fish (approximately)? 6 months
Sounds like water quality issues from overstocking. I would not use bettafix. It won't likely help and it contains an ingredient that can coat his labrynth lung and cause him to suffocate.
The smallest of corey require a minimum of 10g, but some require much much larger. What kind do you have? You need to upgrade the tank or rehome them.
Also, your tank may be undergoing a cycling process. What test kit are you using for ammonia? Strips are notoriously inaccurate.. you should also have a kit for nitrite and nitrate..
You need to be testing daily with a reliable drops kit for ammonia and nitrite and doing an extra 50% change any time you see either. In addition to this a weekly 50% with siphon is needed to remove poop and other debris from the gravel. It is not enough to just scoop water off the top ever.
First you will see ammonia, then nitrite. Eventually, hopefully, you will see ammonia fall and stay at 0 even after a week of no water changes, and finally nitrite. At this point you will be left with only nitrates after a full week of no changes and these can be kept <20ppm by weekly 50% change with siphon. However, cycling will take up to two months to complete and as overstocked as you are it may never fully establish.
As a side note, flakes aren't good nutritional value, and especially with something this small they muck up the water quickly causing excess ammonia. You should look for a good quality pellets whose first two or three ingredients are whole fish, not fish meal or wheat. He should be fed two small meals a day (how many depends on the pellet you pick up) and one fast day a week.
That's the kind that needs 10g. Also if you keep make sure that you are feeding them. There won't be enough algae in most tanks for them to live on.
Not enough water changes during cycling will cause this 100% of the time, depending on how high levels got.
I would get a test kit and see where he's at. If it's not established then he may need to be removed into separate tank for treatment. I'd start with aquarium salt, predissolve it at 1 tsp per gallon. Leave him for 10 days in the salt (can't be used with live plants or coreys). You only need to redose salt along with a water change and then only add back as much as water you actually replace.
how will I know if this is helping? will his fins regenerate?
I have a 2.5 gal tank that I could use while this tank is cycling (assuming it's still in progress, which I will know as soon as I buy test kits in a few moments). How often would I need to change the water in the qt tank? And after the ten days, assuming I see a change, I place him back with the coreys and he should be okay?
the ends of his fins (though it doesn't show well in this picture) are a shiny blue colour, and have been since I bought him. Though the picture is a bit deceiving, his fins don't seem to be decaying.. but I don't know. Is it possible that this is clamped fins and not rotting fins?
Also, I saw somewhere else that you posted about a dangerous spongebob tank ornament. Which is it? I added a pineapple ornament recently (I have taken it out since he became sick) but could this be the cause? And if so, what illness arises in the beta, and is it curable?