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My Pleco Ate My Fish? How this Happen?

Topic: My Pleco ate my fish and there is no question about it. I know what most of you are thinking.. that a Pleco can’t eat a live fish.. but I can’t find my Molly fish anywhere! This has happened in the past before with swordtails and guppies. I thought I was going crazy but now after multiple fish.. The Pleco is eating them! What is going on here? Pleco is 8 inches long and 5 years old.



*Awarded Answer
Reply from Ryan VI know what your thinking is right but I must say that it’s only partially correct. Your Pleco is eating your fish but only after the fish have already died. It’s very common for a Pleco to suck on dead fish and eat meaty meals like this. Especially a descent sized one like yours. I have one that is 12 inches long and he eats dead fish all the time.

The fact of your Pleco eating those small fish while they are still alive is almost impossible. They are just too small an fast for the Pleco. If you search for the phrase “Pleco ate my fish” you will come up with tons of stories regarding this. Your not the only one to blame their Plecos or being the killer. If you think about it… It’s actually quite helpful for them to feed on those dead fish because it really helps the water quality from having dead fish sit in your tank all day while your at work.

pleco eatingAnother thing that happens is people have fish die during the night and that’s when the Pleco feeds the most. They are nocturnal and feed on food like crazy at night. So people wake up and go to turn off lights and come to find out that their fish has been eaten. After searching every square inch of their aquarium and insider filtration system and in their gravel have come to the conclusion that there is only one culprit to blame here.

They are not necessarily killers but more or less just cleaning up garbage that was left behind and the fish has already died. I guess you really have to ask yourself a bigger question is to why your fish died in the first place. You said that you have Molly fish and other live bearing fish and I’m gonna let you in right now and tell you that they die quite frequently. Air commonly used as feeder fish just because they’re very cheap and they don’t live that long of a life span.

Reply from Jeff N:
This happened to me a couple weeks ago and it’s funny that this topic just came up because the exact same thing happened to me. I have a Pleco that is around the foot long and it seems that one of my smaller fish died and he completely disappeared. Was searching everywhere the tank and I thought for sure that he was hiding in the gravel or somewhere because I will need to get rid of him so that my water quality wasn’t that bad.

I did a little research and come to find out that the fish probably most likely died like you guys said and he sat on that as a good meal. I used to have crayfish do this but they want to completely eat the entire fish but more or less just suck a lot of the insides out. I’m not really sure how I feel about this algae eater that also will move over to the other side and eat meat. I thought he was going to help clean my tank a lot cleaner but it is actually got more messy because he poops more than any of the other fish.

Posted by Ashley T: My Sucker Catfish Attacked Goldfish
About a week ago My Black Moor was really sick lying on her side floating at the top of the tank and got attacked by a Pleco damaging her scales and tearing her fins. Needless to say she survived with a full recovery after treating the water with a stress cost and removing the Pleco along with the ornaments that had sharp edges.

  • So glad he/she made it! I’ve never heard of a pleco doing that.
  • yes they are known goldfish killers particularly at night when the goldfish are resting on the ground.
  • My pleco is 3 inches and attacks my 8 inch common sometimes it’s funny but can be serious I need to figure something out.
  • Separating them would be the best option.
  • Usually it is just a missing scale, usually not fatal unless a secondary infection sets in. So keep your water clean, remove any sharp decor and add a little aquarium salt if you’re concerned. If you have any loaches or plecos, i would sepparate them from your goldie tank.
  • Oh I don’t like this. I just lost a Black Moor after 1 week and it started looking like that. I thought it was a parasite and treated it but sadly it did not make it. In the end was overcame with them.
  • Im glad you brought this up because I was going to put a sucker with my goldfish.I’m about to get my 4 year old a few fancy goldfish for her fourth birthday. I’ve been ready like CRAZY (she’s autistic and I worry about the upset that would come from losing a fish, so i’ve been very diligent giving them the best start) the last few weeks, and am wondering a few things:1 – I did my last water change (30%) and am wondering how long between dechlorinator before you can add plant additive safely? I know they say quick cycle should be at least 15 minutes, but want to get that cycled through the water pretty well before adding fish (likely Saturday afternoon)

    2 – I’m running a 37gal tank with about 40lbs gravel. I know I can do 3-4 goldfish in it at this size, but am also considering a pleco eventually depending on algae levels. should i just stick to 3? I have a 12″ bubble wall running a 40gal air pump, so oxygenation shouldn’t be an issue.

    3 – I’m using BioSpira to do a quick cycle with live plants that have been sitting a couple weeks. How long should I let it sit? I know I can “technically” add fish immediately, but would waiting a day or two be beneficial? I have only live plants but worry about there being enough ammonia for the bacteria to thrive without the fish. If I should let it sit a couple days, how long should I leave the dechlorinator to do it’s business before adding it? and should i give time between that and the plant solution i have? how much time?

    4 – How many live plants and/or how much plant cover should I shoot for in the tank? I have 5 very little plants growing like crazy right now, but I know the goldfish prefer some place to hide, and obviously will eat the plants.

    5 – Should I run medication in the tank with the fish when I add them to the tank? will it kill the bacteria and should I just hold off and only attack if a problem arises?

    Thanks so much for taking the time with my extremely detailed questions