Fish Disappearing in Tank. Not Sure of The Culprit

boxingscene

Feeder Fish
MFK Member
Sep 21, 2014
50
2
8
Las Vegas
I have a 750 fresh water and plenty of fish in there, mostly aggressive.

Lately some of my fish have been vanishing without a trace.

Some of the fish vanishing off are 5-6 inches in length and some had size on them.

The only culprits I can think of is the Arawana, who usually stay 4 feet above at the top, the Clownknife who stays to himself, or the Watercow Goby who usually hides in the lace rock caves.

There are several very large fish in there, but the three above are the only likely three with mouths big enough....well the Clownknife's mouth is pretty small now that I think of it, although he is very big.

I have a Marble Cat, but is average in size and I don't believe big enough to take down some of the below fish. I do have some little guys in the tank, like red jewel and bumble bee (among others), who are in that tank day in and day out but probably play it safe and hide out in the rocks most of the time.

I've had two Jack Dempseys vanish, at least two banded Midas, several smaller Africans, a tropheaus.
 

Monstrous

Jack Dempsey
MFK Member
Sep 25, 2013
148
2
33
Singapore
The arawana would only kill the fishes that comes up to the surface to breathe. I think the watercow is the more likely culprit, judging from its big mouth and its stalking ability. Most likely, your fish mistook it for a piece of woodwork and decide to rest near its mouth and got eaten.
 

Evz jardini

Jardini
MFK Member
May 19, 2010
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The arawana would only kill the fishes that comes up to the surface to breathe. I think the watercow is the more likely culprit, judging from its big mouth and its stalking ability. Most likely, your fish mistook it for a piece of woodwork and decide to rest near its mouth and got eaten.
I too think this is the most likely culprit , if it was your aro I'm sure you would have caught it chasing them during the day while lights are on (what type of aro is it out of interest ? )

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boxingscene

Feeder Fish
MFK Member
Sep 21, 2014
50
2
8
Las Vegas
I too think this is the most likely culprit , if it was your aro I'm sure you would have caught it chasing them during the day while lights are on (what type of aro is it out of interest ? )

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It's a silver arawana.
 

boxingscene

Feeder Fish
MFK Member
Sep 21, 2014
50
2
8
Las Vegas
I also keep the blue moon lights on all night so some of the smaller guys can see night stalkers coming, but that hasn't helped the issue.
 

Evz jardini

Jardini
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May 19, 2010
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My moneys on the goby , what's your aro like during the day with the cichlids any chasing , nipping ? If he leaves them during the daylight it won't be stalking them at night , during night hours your cichlids will have no idea where the goby is once they float past that big mouth there lunch , if it happens again check to see if your goby has a full belly in the morning

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boxingscene

Feeder Fish
MFK Member
Sep 21, 2014
50
2
8
Las Vegas
My moneys on the goby , what's your aro like during the day with the cichlids any chasing , nipping ? If he leaves them during the daylight it won't be stalking them at night , during night hours your cichlids will have no idea where the goby is once they float past that big mouth there lunch , if it happens again check to see if your goby has a full belly in the morning

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The Arowana never chases anyone but he sometimes goes halfway down, around the two foot area, and just swims around. The Goby, hard to tell if his belly is ever full. He stays inside the rock almost 24/7. Every now and then he pops his fat head out to look around on the day I feed pellets/flakes and the day I feed feeders.

My money is likely on the Goby as well, as I've never actually seen him eat anything. He might be eating feeds when they run in the rocks to hide from others, but I've never seen him eat anything. He looks quite healthy so he is certainly eating.
 

Evz jardini

Jardini
MFK Member
May 19, 2010
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Try and lose the live feeders if you can get everything eating pellets there less likely to eat tankmates in my experience , either that or rehouse the goby for a while see if it stops , or get bigger tankmates he can swallow not much else you can do really unless you don't mind feeding your goby expensive feeders ;):D

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boxingscene

Feeder Fish
MFK Member
Sep 21, 2014
50
2
8
Las Vegas
He wont be able to eat the majority of the tankmates. Most of them are far too big for him to take down.

I do agree about rehousing him. It will be hard. My tank is four feet deep and he stays in the rock almost all the time. I may have to wait until he gets his ass out and go for it very quickly. I have a pond net (five foot long) which I used to catch a shovelnose that I needed to bounce from that tank weeks ago. I have a 60 gallon so I'll throw him in there for a while to see if the vanishing stops.
 
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