I had a betta a few years ago who was the most active and happiest fish I've ever seen. He enjoyed hide-and-seek, watched me work at my desk, and constantly swam around his 5 gallon tank. He was a strong swimmer, a big eater, and lived a relatively good, long life.

A few months ago, I decided to pick up betta-keeping again, expecting similar results. I re-did all my research again to make sure I gave him the best environment, but he's a weak, lethargic little dude. I don't know if I've done something wrong, or if he's old, it's his personality... you name it.

Here's Odahviing's tank specifications:

  • 5 gallon, carbon filtered tank (I have to turn the filter way, way down, because he has a hard time swimming in any sort of current, so the filter is more of a dribble).
  • Heat maintained around 76-78 °F (24-26 °C).
  • Decor: 2 moss balls, 1 zebra plant and 1 madagascar lace plant (my plants thrive and I make sure to remove spent leaves), 1 fake log, black sand substrate at the bottom.
  • 25-50% water change every 2-3 weeks, treated with conditioner. I test pH, ammonia, nitrite, nitrate, etc. levels generally each change. All are appropriate, except ammonia is slightly higher than 0 (just barely).
  • Fed betta pellets 2 times a day; 3 pellets before noon and 2 pellets past noon.

About a month ago, I moved him to my desk, where I spend a lot of my time when I'm home. He seemed to get a little more chipper, being closer to the action, but only a little bit. He spends more and more of his time lying still in the plant leaves, since they're big enough to support him, or sitting at the bottom of the tank. He does occasionally take a lap or two around the tank, and still enjoys chasing falling food pellets (he prefers chasing them to the bottom than to eating them at the top). He does eat less now, and much slower.

Maybe I'm a paranoid fish owner, but I'm always worried he's sick and/or dying. Any advice on why my fish is so slow, weak, and lethargic? Is he just really lazy?

3 Answers 3


I've kept many bettas over the years. And can say they all have their own personality. And some are certainly more active than others. But based on his decreased appetite, I'd say he isn't the healthiest betta. What you describe - eating less than before, prone to picking at food on the bottom - is often what I see in older and unhealthy bettas. Healthy bettas are hungry bettas, even if they aren't very active.

Btw, I'm not suggesting you need to change anything or you are doing anything wrong. It sounds like he has a sweet setup. And moving him someplace where he will see more movement around him was a good idea. But just like people, some are just more healthy than others. Or he may have been much older than you thought when you got him. If you get an adult at a pet store, he's probably already a year old, possibly even more. So there may not be much you can do.

The only things I might recommend are:

1) Since you are seeing some ammonia, reduce to feeding him once a day. Basically half of what he is getting now. That ammonia may be from uneaten food. Its possible thats making him more stressed. Though I doubt that's his underlying problem, it may be making it worse.

2) If you can adjust the heater, bump it up to 26 - 27 °C (78 - 80 °F) to see if that livens him up. If the heater is a fixed temperature one, you can cover the tank with something (make sure it doesn't fall in) and that may help raise the temperature.

3) Research those plants to make sure they aren't known to have problems with fish. I doubt it (especially moss which will be safe), but it never hurts to check.

  • These are great suggestions. I'm going to start doing small water changes every other day (maybe 10%?) to try and get the ammonia down. Since I have been feeding him less, as a result of him eating less (he's had a couple fasting days now), he's been a little wigglier, which is promising. I'm betting he is a bit on the older side, but definitely want to give him a comfortable life, however long it might be. Thanks!
    – Gwendolyn
    Commented Dec 19, 2018 at 19:08

Unfortunately I cannot answer whether your fish is sick, I am not a fish owner myself, but if you think it might be sick, talk to a vet.
But for the question of fish personalities. It is a topic that has been researched over the past few years and the general conclusion is that the multiple species researched had personalities. This was mostly done in the area of 'shy' and 'bold', generally looking at how much risk a fish dared to take in presence of a predator. The conclusions of these studies were that: yes, fish have personalities. Some of it can be found here for example: https://phys.org/news/2017-09-fish-complex-personalities.html
I cannot easily access the research papers anymore but as far as I'm aware activeness in fish can be related to personality. But whether that is the main reason for your fish being inactive I cannot say.


Bettas are not active and do not want moving water as you correctly concluded. They get active for another betta or some moving food like mosquito larva.

  • 2
    I would most definitely argue “bettas are not active” because they most definitely can be. It’s a common misconception and what perpetuates the idea that you can keep bettas in small tanks.
    – Gwendolyn
    Commented Dec 16, 2018 at 17:22

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