Why did this happen?

[fluxive]

My Betta fish suddenly started swimming erratically yesterday. Water params are good, 0 ammonia, 0 nitrite, 5 nitrate. Tank is a 10 gallon with a sponge filter, kept at 78F. He's been eating normally but now he's just darting around like crazy. What's going on?

[zenoxa]

Sudden erratic swimming can be caused by several factors. First, check for any recent changes in the tank, like new decor or chemicals. Second, inspect his fins and body for signs of parasites or injury. Lastly, consider if he's been exposed to sudden light changes or loud noises. Bettas are sensitive to environmental shifts.

[folkia]

Yeah, my Betta did the same thing when I added a new piece of driftwood. Turns out it was leaching tannins too fast and freaked him out. Maybe something similar's happening here? Check if anything new's in the tank, even if it seems harmless.

[flavion]

Yeah, my Betta did the same thing when I added a new piece of driftwood. Turns out it was leaching tannins too fast and freaked him out. Maybe something similar's happening here? Check if anything new's in the tank, even if it seems harmless.

That's a good point. Also, how often do you do water changes? Sometimes buildup of dissolved organics can cause stress even if the basic params look fine.

[canvas]

I'd also look at the flow from your sponge filter. Bettas prefer calm water, and if the flow's too strong, it can stress them out. You might need to baffle it with a pre-filter sponge or adjust the air pump.

[fluxive]

Thanks for the suggestions, everyone. I did add a new almond leaf a few days ago, maybe that's it. I'll remove it and see if he calms down. The flow's pretty gentle, but I'll double-check.

[stoney8]

Could be the leaf, but also check for tiny snails or pests. Sometimes hitchhikers freak out Bettas. My guy went nuts once because of a tiny bladder snail he couldn't catch.

[greenleaf]

Haha, Bettas are such drama queens sometimes. Mine once freaked out over his own reflection for a whole day. But yeah, the almond leaf is a likely culprit. They're strong stuff.

[Falcro]

My Betta did this when the heater malfunctioned and the temp spiked. Maybe check your heater's working right? Just in case.

[zenoxa]

My Betta did this when the heater malfunctioned and the temp spiked. Maybe check your heater's working right? Just in case.

Good call. A sudden temp change would definitely cause stress. OP, what's your heater's brand and age? Some are more reliable than others.