# Pleco attacking Betta?!?!



## Ethand (Sep 1, 2018)

Hey guys, after I noticed my Betta chasing one of his injured Tetra tank mates last week (after 6 weeks of him not paying them any attention whatsoever), I decided to move him into a new tank. This new tank had been given to me with several fish that were way too big for the size of tank it was, so I rehomed them to people with bigger tanks. I kept the smaller pleco, though, since I figured he’d get along great with the Betta, since he’s slightly bigger than the Betta & a bottom-dweller, so my Betta wouldn’t attack him.
I never considered that the Pleco might attack the Betta though?!
I recently did a 100% water change, scrubbed the glass & added some new plants & more driftwood to the tank. Tonight I decided to watch the Pleco after I turned off the lights to see if he actually ate any of the cucumber I had placed in his tank, since I never had any luck getting him to eat blanched Zucchini. Within about 1min of the lights going out, he was zooming around the tank. To my surprise (& horror), though, he went straight up along the driftwood to near where the Betta was swimming & attacked the Betta!! A similar thing happened 2 more times within about 10mins of me watching! I always thought these 2 got along great, because in the day, they’re fine.... it never occurred to me that the Pleco night attack the Betta?! 
My Betta is now in a breeding tank overnight to protect him, as my only other tank I have is the one with the Tetras. I’m thinking tomorrow maybe I should swap the Pleco into the Tetra tank & bring the Cory cat from that tank into my Betta tank?! I don’t even know what to do - I didn’t realise that Plecos could be aggressive!!


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## Rainbo (Nov 23, 2015)

What size tanks, and what species of pleco? From what I am reading plecos don't really hunt their tankmates, but as they get larger they will defend their territory from other fish, and if the aquarium isn't large enough the aggression will be worse.


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## Ethand (Sep 1, 2018)

The tank is a 10gal, the tetra tank is 12gal. I’m guessing he’s a common Pleco, no bristles, but not certain. Seems unlikely he’d just be defending the tank given he used to share it with like 5-6 other fish & now there’s only one? And there’s more hiding spaces now & he’s fine in the day...? This just looked like he was hunting the Betta - he’d swim along the driftwood until he reached a point as close to the Betta as possible, then he’d wait til the Betta was facing the other way & quickly dart after him! I’d have thought if he wanted to just threaten/scare off the Betta to protect his territory, he’d do that any time of day & would swim straight at him to scare him off?


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## Wyvlen (Nov 14, 2018)

A common pleco!!!!??? Those get about 2 feet long, honey. You need to rehome that poor thing, or get an extreme tank upgrade.

Since you took out the other larger fish, now there is room for him to claim his territory. When a tank is overstocked, territorial fish don't have any territory to claim, so they're (usually) more docile or stressed.


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## Ethand (Sep 1, 2018)

Sorry it’s a female bristlenose Pleco... I didn’t know what type it was at the time of posting - I just knew it was the most common one I’ve seen in tanks... I know these do also eventually grow to be quite large, but currently she’s good in this size of tank given her current size. I can’t go a bigger tank, so will rehome her to my friends big tank once she outgrows this one.
I’ve since read up on Plecos being attracted to something in the slime coating on goldfish & that Plecos can kill goldfish by sucking off their slime coating. I’m guessing this is the same with the Bettas.


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## Kirri (Nov 20, 2018)

I have a female bristle nose pleco about an inch and a half long (still very small) in a 20g fully planted tank with my betta. They've been together for 8 months with 0 issues. Last night though, she attacked my betta. Not sure why. I woke up to find my betta with his right side mauled. He's a dumbo halfmoon, his right fins are a mess and he's missing scales from his side. His right eye is also popeyed and cloudy. I have him in a hospital tank right now and have treated with a quick salt bath. I have no idea why the pleco attacked him last night after 8 months of peace. But I'm sending the pleco to a friend's pond. I had planned on putting her in my bigger community tank when she was bigger but I don't trust her in any of my tanks now. I've never had a pleco attack any of my fish before. It's left me really uneasy.
I'm not sure if Specter(the mauled betta) is going to make it. I'm going to be devastated if I lose him.


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## RussellTheShihTzu (Mar 19, 2013)

Thank you for sharing and Welcome to the Forum! :wave:


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