My betta fish just died, am I doing something wrong?

Lethargic and lack of appetite are common symptoms of a cold betta. I had a betta unexpectedly end up in my care at one time and had no heater for her for about two weeks. The difference was like night and day when I finally got a heater into her tank. She went from being a sulking, standoffish, drab fish, who barely ate a morsel, to being a brightly colored beauty who ate ravenously and wanted to know what everyone was doing.

The heater is essential. Keep that tank at 76*F-84*F (80*F being a good place to set the thermometer) and you will have a much healthier and happier fish.

Every tropical fish needs a heater

Betta's need a variation of foods, get like 5 kinds of food and vary a bit

How many water changes did you do? For a 5 gallon you should do 30% changes weekly

Is the tank cycled? What are the ammonia, nitrite and nitrates levels?

Yes, bettas require heaters. They are tropical fish (from what used to be Siam where it is hot) and need the heater set to 75-82F.

The cold water killed him, bettas are a tropical fish, therefore, they need a tropical temperature. When a fish becomes lethargic the organs will slow, eventually resulting in liver failure or something similar. You obviously didn't do enough research prior to buying. You'll most likely end up getting another betta, so I will leave you with this information:

**Removed housing info to make room for reply, will email if necessary**

Bettas are carnivores, feeding just flakes or pellets is not a proper diet. In the wild betta fish eat insects, insect larvae and smaller aquatic creatures. Being so it is best to try and mimic the diet the best you can. Flakes and/or pellets should only make up half the diet. Frozen or live foods such as bloodworms, brine shrimp, mysis shrimp, mosquito larvae, daphnia and tubifex worms are excellent foods to keep your betta happy and healthy. You do not need to feed all of these foods, just one or two would be ideal. Freeze-dried foods have very little nutrition value, and are pretty much just a waste of money. I would also recommend switching to flakes rather than pellets, sometimes pellets can be too difficult to eat because they are often too large for their little mouths, so flakes are a much better alternative. One thing to keep in mind is a bettas stomach is around the size of its eye, so make sure to feed very sparingly, if given the opportunity they will pig out. I would advise feeding flakes one day, and frozen food every other day.

I strongly recommend planting your aquarium, plants are very beneficial to aquariums, especially the smaller, harder to care for aquariums. Some of the benefits they make the aquarium look more natural, help the aquarium cycle faster, help the aquarium stay cleaner, help remove ammonia, nitrite and nitrate and give the inhabitants more coverage.

Here is a great list I made up for easy to care for aquatic plants:

Water Sprite, Willow Leaf Hygrophilla, Water Wisteria, Small Leafed Hygrophilla, Java Moss, Anubias, Common Sword Plant, Ambulia, Java Fern, Banana Plants, Valisneria, Cryptocoryne, Hornwort, Christmas Moss, Frogbit, Hairgrass, Dwarf Hairgrass, Moss Balls

*Edit - @ Blondie and Kalman kane - Seriously? Fish don't just die for no good reason. That's like saying a 4 year old died, just because, there's always a reason. The obvious reason was because a heater was not used. Bettas are a tropical fish, they require a temperature between 76-82F. When you keep a higher end tropical fish like a betta under a temperature of 74F, it will make the fish lethargic and it will eventually go into hypothermia. When hypothermia sets in the organs will slowly begin to shut down, creating a very slow and painful death.

A fish "past its prime" is an old fish, the bettas you find in pet stores are relatively young. Betta fry will become easy to sex around 8 weeks and get their adult coloration around 11-12 weeks, at this point, they are then sold to pet/aquarium stores. When people buy them they will be between the ages of 12-20 weeks. Bettas have a lifespan between 5-7 years, so no, they are not "past their prime".

Forgive me for spending 20-40 minutes on average on a question (not including the edits, and the personal back and forth emails), to guide people in the right direction, so the same mistakes aren't made again. "Taking the fun out of fish keeping" Now that's just silly. Is that what you call fun? Killing fish? Why fail a bunch of times, costing the life of tons of fish, just so you can have some trial and error experiences? Not many people think about it but, fish have similar pain receptors and nervous systems are a lot like ours. So, could you imagine your lungs burning, eventually dying of suffocation. Or having all you organs slowly shutting down? Sounds pretty painful.

I believe properly caring for fish and having a healthy aquarium, with healthy fish would give you a lot of pride and self satisfaction. I'd definitely chose that over buying fish, only to have them to die, or wondering what happened. Only to reach out for help as to what happened, to just have people say "Oh, don't worry, it's just a fish" or "Accidents happen" or "That fish was just past it's prime" as it was just a dud fire cracker. I take caring for my fish seriously. The reason I'm on this website and many other forums is because I want to help other people, so they can be proud of what they did, keeping aquariums can help with stress, anxiety and depression, it's helping me, perhaps, me and all the other "fish geeks" want other people to feel the passion and the great sense of accomplishment we feel.

i agree with you blondie.fish nerds a good term for some of these weirdos here.reading how they answer makes you think they were born with an aquarium up their anuses.they're taking mostly the joy of others in fishkeeping by spouting all these goobledygooks.my take on these is the betta was probably way past its prime when bought.thus,no matter what you do,its days were numbered.sorry to hear bout it bud.goodluck for the next fish.i read a good one here about buying fish while young,that's a good thought. cheers!

Ask yourself, where did you purchase the fish and was it clean there? Did you condition the water? And did you have a sudden change in his/her diet? if there was a yes in any of these, reply back and I will help if you want.

sometimes fishes just die out even if we thought we've given them the best care possible.sometimes they're already sick even before we've brought them to our homes.sorry for your loss.but next time you plan to buy a new pet,it would be best to examine them closely.make sure they have bright colors and no nipped fins.fishes that are sick often have dull gray eyes.so look carefully for these signs.and in all my times of fishkeeping,i realized that the best time to buy fish is when they're still small.best that you grow them to maturity yourself.

How looping did you have it for? Did you change the water? Did you feed it to much? It could have been anything p.

Don't listen to all these fish nerds. Betas can be fine with a heater and it sounds like you did everything fine and that you were more than humane. SOmetimes fish just die.