*Context: i recently started taking care fo the fish at my college. i moved this sunfish to a larger tank with more stuff to interact with. In the past, everyone has known her to be "aggressive", doing things like "attacking" hands that were put into her tank, crashing into her own reflection, etc. I moved her from a 15gal to a 29gal tank about 2 months ago. Since then, shes also been fed more, as she was very underweight, and while likely biased, I believe she is healthier now. Recently, she started doing this. She swims ariund in circles and charges the bubbles and she will do it for awhile.

People I work with (who self-admittedly dont have much experience with aquariums) say that this seems like aggression to them and that it may be stressing her out/burning a lot of her energy, which would not be good since we are still trying to gain weight. However, I think she is playing. She always does this behavior right after I feed her. Maybe she is just in predator mode and attacking anything that moves? Or she just has more energy now and since shes gotten used to her new home, shes comfortable exploring and being crazy? what do you guys think?



Posted by gumihe_

19 Comments

  1. LongjumpingYak4663 on

    Probably needs a bigger sized tank. Never had sunfish but based on this video they seem to be super active fish.

  2. GiraffePretty4488 on

    To me this fish looks bored or stressed. It probably needs a lot more room to feel like it can explore and settle in somewhere. 

    That said, I am not familiar with the species. 

  3. AggressiveFigs on

    So I have a number of longear sunfish, and while online I’ve seen material saying 29 gal is the min, it really should be closer to 55. They need a 4 ft tank to swim back and forth. This to me doesn’t look like aggression, but rather a stress response. She just may have not been doing it before because she didn’t even have room for it in the 15.

    Is it wild caught or tank raised? If you get them really young you can make a 29 work if they grow up in it, but wild caught struggle with something this small.

  4. Plenty_Kangaroo5224 on

    That’s a stereotypy—a repetitive behavior commonly seen in zoo animals with inadequate space and mental stimulation. Sad. That is not play.

  5. The tank is waaaaay to small. At minimum 120cm lenght. And are that artificial plants and rubbish in there? Please remove all that stuff.

  6. Other people have already helped address the biggest problem which is the tank is too small etc

    As a side note; is there anything you can do to offer them direct enrichment? Maybe dropping live black-worms in for them to hunt down and slurp?

  7. Aggressive-System192 on

    Tank too small. The fake plants look like dollar store stuff… are they made to go in a fish tank? If not, might leach chemicals in water over time.

  8. -CuteAsDuck- on

    The kindest thing to do here is provide a bigger tank or give it to someone who is able. I think any adjustments made in this space will only help short term at best. I would like to note that it’s great that you’re here & trying to do the best you can for this guy/gal.

Leave A Reply