Aggressive plecostomus behavior

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fungi_fox
Posts: 3
Joined: Thu Oct 10, 2024 5:13 pm

Aggressive plecostomus behavior

Post by fungi_fox »

My pleco has been acting super aggressive lately, chasing my other fish and even nipping at them. It's a 55 gallon tank with plenty of hiding spots, but he's still being a bully. Anyone else dealt with this?
BoldRom
Posts: 12
Joined: Thu Oct 10, 2024 3:38 pm

Re: Aggressive plecostomus behavior

Post by BoldRom »

Yep, plecos can get territorial, especially if they're older or if the tank's crowded. What's your water change routine? Sometimes poor water quality can stress them out and make 'em act up.
dawnfly9
Posts: 2
Joined: Thu Oct 10, 2024 4:43 pm

Re: Aggressive plecostomus behavior

Post by dawnfly9 »

I've got a similar issue with my common pleco. He's in a 75 gallon with driftwood and caves, but he's still a jerk to my cichlids. Gonna try rearranging the decor to shake things up.
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trollmaster
Posts: 18
Joined: Wed Feb 09, 2022 3:39 am

Re: Aggressive plecostomus behavior

Post by trollmaster »

BoldRom wrote: Sun Jun 22, 2025 4:17 pm Yep, plecos can get territorial, especially if they're older or if the tank's crowded. What's your water change routine? Sometimes poor water quality can stress them out and make 'em act up.
Agreed. Also, check if he's getting enough food. Hungry plecos can get feisty.
ratchet
Posts: 7
Joined: Fri Feb 23, 2024 10:56 pm

Re: Aggressive plecostomus behavior

Post by ratchet »

Mine chilled out after I added more algae wafers. Maybe yours is just hangry? How often do you feed him?
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copperkit
Posts: 19
Joined: Tue Feb 01, 2022 10:25 am

Re: Aggressive plecostomus behavior

Post by copperkit »

Plecos are weird like that. Mine's cool with everyone except my angelfish, which he hates for some reason. Tank's a 40 breeder with sand and driftwood. No clue why he's got a vendetta.
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Florionix
Posts: 7
Joined: Tue Jul 23, 2024 2:17 pm

Re: Aggressive plecostomus behavior

Post by Florionix »

Aggression can also be a sign of spawning behavior. Is your pleco male? Males can get super protective of their territory when they're ready to breed. Might explain the sudden change.
briarbrook
Posts: 1
Joined: Thu Oct 10, 2024 8:37 pm

Re: Aggressive plecostomus behavior

Post by briarbrook »

Or maybe your pleco's just a jerk. Some fish are like that. Mine's a total diva, but he's got personality, I'll give him that.
flintx
Posts: 3
Joined: Thu Oct 10, 2024 4:36 pm

Re: Aggressive plecostomus behavior

Post by flintx »

Florionix wrote: Sun Jun 22, 2025 6:59 pm Aggression can also be a sign of spawning behavior. Is your pleco male? Males can get super protective of their territory when they're ready to breed. Might explain the sudden change.
That's a good point. OP, how old is your pleco? Males usually show more aggression as they mature.
stella9
Posts: 3
Joined: Fri Jun 21, 2024 1:33 am

Re: Aggressive plecostomus behavior

Post by stella9 »

Mine's a chill dude, but he's got his own cave and I feed him zucchini twice a week. Maybe try diversifying his diet? Could be a food thing.
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