Cannibalism In Tank


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Jun 11, 2008
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I'm relatively new to the wonderful world of tropical fish keeping. Apart from an unexplained guppy death early doors, everything has gone swimmingly (excuse the crap pun)...until now! Cannibalism in the tank??? i don't remember signing up for this!!!

I have a 25 litre tank with one bristle nose catfish, one guppy, two clown loaches, two glass catfish and one male gourami (blue/orange). i did have a female gourami (silver/blue) until she passed away and her so called pals dined on her. Let me set the scene a little...male gourami was relentlessly bullying his 'wife' and she had nowhere to escape (i take full responsibility for this as a tropical fish expert recently told me my tank was far too small for two gouramis...sadly, the pet shop that sold them to me didn't divulge this important info). I built her a little ‘cave’ out of rocks and I have a plant which she would hide behind, but he always found her and resumed headbutting/nibbling. she developed a red, open 'sore' on her side (he also bit a chunk out of her tail) and she started to act even more timid than usual. i researched the ulcer and it appeared to be stress-related. i tried to put her in the floatation tank, but she was so nervous and jumpy from her 'husband’ being a pest, that she just freaked out. i felt i was doing more harm than good, so left her in with the others. i started to put tea tree medicated drops (forget the name? got it from a tropical fish shop) into the water to aid the healing process, but didn’t see any difference.

Now here’s the traumatic part. I went away for the weekend and (I hold my hands up) forgot to ask my housemates to feed the fishies. In my defence, I was on cloud nine about my brother’s baby being born and it completely slipped my mind. I’ve read that well fed fish can last a whole week without food, but I know that's no excuse. So I came back on the Monday, turned on the tank light and saw what looked like a ball of white fluff. At about the same time I realised my female gourami was missing, it dawned on me that what I was looking at was her tiny bones.

After a whole hour of crying and feeling pretty shaken up, I finally removed the ‘body’. Just prior to this, I’d seen my bristlenose catfish sucking on the remains! Aren’t they supposed to be veggies?!?!?!

So now my tank is harmonious because there’s no bullying. I won’t make the mistake of buying any more gouramis. But I’m left feeling a little disheartened at the savage behaviour of my ‘cute’ fish that I love so much.

I like to think that my gourami passed away and THEN the feeding started. But how will I ever know?! Other than my catfish, I didn’t see anybody else showing interest in her remains. I know they are just fish and they are only doing what nature tells them…but it just seems so brutal!

I’d be really interested to hear if this has happened to anybody else’s fish and also if you know of a tablet I can buy/a method I can use which would feed my fish systemically whilst I’m away for a few days. My boyfriend bought me a tablet that lasts a whole week, but this would surely be too much for just a weekend?? I’m away quite a bit so it would be really helpful and will hopefully divert any future disasters.

I feel like the worst fish keeper in the world!

Any advice or tips would be much appreciated.
your fish wouldn't 'feast' upon each other if there was nothing wrong with them, so shouldn't worry about not feeding them over the weekend.
fish tend to be opportunists so when there is a supply of meat available they will tuck in. i would suspect that all of your fish ate some at some point, especially the loaches.
as for the loaches they will get far too big for your tank i'm afraid.
its likely that your male gourami was harrasing the female to mate with him, and she obviously wasn't interested and eventually gave up living, thats when the others will have had a feed.
its just what fish do i'm afraid.
oh huni, don't be so despondent, we all make mistakes you are far from the worst fishkeeper ever. The simple fact that you are upset by this and wanting to learn to do things right tells us that you care, there are a lot of people out there who do not care about their animals at all so your a whole way away from that.

firstly i can tell you with 100% certainty that she did die before they ate her. it's very common, fish are opportunistic feeders and virtually any of them will feed on a dead body. so I hope that is a small weight off your mind. It's totally normal for remains to be eaten.

fish exist in the wild on the brink of starvation, they can go several weeks without food, a weekend away would be no problem, no need to get anyone to feed them or do anything so don't beat yourself up over that. for a couple of days there's no need to feed them, the feeder blocks are bad because they mess up the water quality, it's actually better to leave them without food that to feed them using that.

the simplest way to ensure they get the right amount of food (particularly if you have housemates) is to get someone else to feed them, but to set out portions of food, either use those pill boxes you get when people are on a lot of medication, they're divided into daily compartments, or just wrap up portions of food in foil. the instruct your housemates to just feed one package of food a day.

you can get automatic feeders where you put in the food, set a timer on it and it drops food into the tank at regular intervals, you can get them from a few pounds up to like £30/40. While you don't need the mega expensive ones it's best to not get the really cheap ones because they are a bit unreliable.

it's only if your away for more than a week that you need to worry about it though, anything less is fine.
its common in larger tanks for fish to just go 'missing', and no remains are ever found, as they are eaten.
as for feeding as long as the fish are routinely fed up to the point of you leaving there is no reason why they should not survive a few daus or a week as you've suggested.
Unfortunately you seem to be the victim of poor (if any) information from you LFS. Your tank is at least 6 times too small for the fish you are keeping. Clown loaches in particular grow to a substantial size. They are also better in groups of at least 4. Also glass cat fish should be in groups of 6+. Your female gourami would have died from stress due to the fact there is little or no refuge in an overstocked tank. All fish will feed upon the remains of dead fish in a tank, this is completely natural behaviour for them, if a little unpleasant for the keeper.

I would consider rehoming the loaches, or upgrading your tank size to something more suitable 200L + or eventually you will have more 'casualties'. I have made all the mistakes under the sun whilst keeping fish over the last few years, and wish I had got better information at times of purchase etc. All I can say on the subject is LFS are sometime driven by the desire for your £ rather than the needs and requirements of your fish. I would suggest that you thoroughly research all your fishes needs and then decide what is best for them depending on your financial situation.

I personally would not bother with feeding blocks unless you are intending to be away for more than a couple of days, fish will be fine for that length of time without food. Longer than that then consider some kind of auto feeder, ther eare lots around to suit most tanks.
wow, thanks for all your replies!

it's certainly a relief to know that my gourami would have already been dead and that it's not just my fishy friends who like to feast on dead bodies!

your comments about feeding were really helpful and will also stop me worrying about weekends away.

everybody i've spoken to about clown loaches (since i put them in the tank) has said they are going to grow far too big! what a shame. they are so cute and funny...i love the way they swim on a tilt and sort of wobble along in a comedy fashion!

might have to re-think a few things.

does anybody know what else bristlenose catfish like to feed on as a treat, other than cucumber? i read somewhere about potato??? is that true?

thanks again for all your help.
yes potatoe is good, as is courguette (or zucchini depending which part of the world you are in) likewise peas make a nice treat, get some sinking catfish pellets and algae wafers too :good:
thanks miss wiggle!

i live in london so i'm definitely a courgette girl. i'll have to try him with some of that! he's my favourite, he keeps me entertained with his scuttling about and sucking like a mad thing.

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