Betta Fish Warning Signs

The following list of behaviors are not normal for betta fish and should put you on alert immediately. As soon as you notice them, check your fish’s water conditions (you did get that water test kit, right?) and check the temperature of the water.


If either of those two things are off by even a little, that could explain these symptoms. Even temperature changes of 2 degrees can weaken a fish, especially if its health has been compromised (and if you bought it from almost any pet store, its health has already been seriously compromised.)

Not eating. See the feeding section on page for what to do about a fish that won’t eat.

Swimming much slower than usual or not at all. If none of the other symptoms in this list apply, you may have a problem with the water, or the temperature in your fish’s tank may be too cold. Check both water and temperature. If both are OK, try raising the temperature 2 degrees and see if your betta becomes more active.

Swimming sideways. This could be a problem with your fish’s swim bladder. You’ll need to treat your fish with an antibiotic in a shallow tank, in about 3-4 inches of water. Do frequent water changes – every other day. Swim bladder problems can be a result of a physical trauma (like the fish actually getting hit somehow) or by chronically bad water. It is difficult to treat and does not have a good outlook for recovery.

Floating upside down. Again, possibly a swim bladder problem. You may be seeing the last throes of dropsy. See #12

Rubbing itself again tank decorations. This could be parasites, the beginning of ich or velvet, or just poor water conditions. As with any problem, check your water and temperature first. Then inspect the fish very carefully. Are any parts of its body or fins grayish or cottony or are there any small white, grey or tan colored spots? If so then you’ve probably got ich, velvet or a fungus. If you see any thread like things hanging from your fish’s vent (where it poops from) or its gills, then you’ve got a parasite problem. If you see nothing abnormal, you may have caught a problem early – do a 30% water change every other day until the fish stops rubbing or the symptoms develop enough for you to identify the problem.

If you see the grey or white cottony patches, it’s a fungus or more likely a bacterial infection, and should be treated the same way you would handle fin rot (see #8). Get either mercoruchrome, gentian violet or methylene blue and spot treat with a qtip. The ifsh should be isolated from all other fish, and you should clean off all equipment that comes into contact with this fish with a 10% bleach solution, then rise them clean. If a bacterial infection is advanced, you may lose the fish.

If you saw the little grains of salt, your fish probably has ich. This is an extremely common problem and is quite easy to treat. You don’t even need a hospital or quarantine tank, because by the time you can see ich, it has already infected your entire tank. Don’t panic, but don’t wait around, because ich will spread fast and if left unchecked, it will kill your fish. Get some ich treatment from the pet store (either formaline or malachite green or whatever your good friend the smart pet store employee recommends). Treat the entire tank per the instructions on the bottle.

After all the fish look good for a week, do two 30% water changes to get most of the ich treatment out. And don’t throw that ich medicine out: you’ll probably need it again.

Fins clamped tight against its body. Ammonia. Way too much of it. Do a 70% water change immediately, and do another 50-70% water change again the next day. Seriously consider adding or upgrading your filters, and commit to cleaning your tank and doing way more water changes. This is, of course, unless you have a new tank (less than 2 months old) or you just added a bunch of new fish. If that’s the case, your ammonia problem is because your tank isn’t cycled properly.

Skin or fins discolored or covered with what looks like cotton, salt or fine dust

Fins getting smaller. If your fish is in a community tank, one of your betta’s tank mates may be chewing on his fins. Observe carefully to see who it is. If your betta is alone, and the shrinking fins don’t look torn, its probably fin rot. This is a common problem, and is caused by really nasty water conditions.

Immediately change at least half the water in the tank, and do it again the next day. Going forward, you need to clean the tank at least twice as often as you have been. Fin rot can spread fast, but it is treatable and the fins will grow back… but it will take time, and they may not be as beautiful as they were before. To treat it, get yourself either mercurochrome (many households have this on hand in the first aid drawer), gentian violet or methylene blue. The last two are available from pet stores. You’ll need to catch the fish in a net, and spot treat the affected areas with a cotton swab dipped in either 50% diluted mercurochrome, or the gentian violet or methylene blue. To boost your fish’s recovery add 1 tablespoon of aquarium salt (or kosher salt, but not regular table salt) for every 5 gallons of aquarium water. Keep testing your water to make sure it is 100% ammonia free. Fin rot can be accompanied by secondary infections, but the salt treatment may help or prevent those. Don’t let fin rot get out of hand – it really eats fins fast. If you see if at night and can’t get to the pet store until morning, at the very least, do that water change and add kosher or aquarium salt. If will make a difference until you can spot treat the fin rot.

Cloudy or protruding eyes

Floating to the top… not swimming, but seemingly unable to stop itself from floating to the top

Struggling to get off the bottom of the tank, and eventually just staying on the bottom of the tank.

Any part of the fish bloated or swollen. This could be a tumor, but more likely its dropsy. Dropsy is bad. Its fairly rare, but you are witnessing major organ failure in your fish, and probably its last days or hours. Recovery is unlikely.

Staying next to the heater all the time. Your fish is cold. Either turn up the heater or get a more powerful heater. If you have a very large tank (more than 40 gallons) you may need two heaters placed on either side of the tank to keep it toasty.

Feces trailing behind the fish. This is a sign of constipation, and means you have been overfeeding your fish. Cut the amount you feed by half and this unslightly problem should go away. If it doesn’t cut back on how much you feed again.