Eeek! My Tilapia have disappeared

[James Rubasch]

Help!  I had bought 24 3-4" fingerlings in January.  12 were Kahalu'u Red and 12 were Kahalu'u Black.  Due to the tank being black, I had a hard time seeing the blacks at any time of day, but I knew they were in there because a flashlight would catch their movement.

The reds are easier to count.  They are now ranging between 5-7 inches.  Last week, I noticed that there seemed less reds in the tank, but I just chalked that up to bad eyes.  Today, I lift off the tarp that covers the tank and there are only 13 fish TOTAL!  No bones on the bottom, no excessively "fat" fish, no remains coming out of the drainpipe in my grow bed.  I feed them 2-3 times per day, and though they eat enthusiastically, they stop eating after a while.  Is it possible that they are eating each other?  I have pretty much ruled out predators.  I have a dog, so no cats in the yard.  The tank sits on a platform and the top of the tank is 4 feet above ground.  I have seen no fish on the ground, but they couldn't jump out anyway because I have a shade cloth over the tank.

None are spawning yet, none seem aggressive, and they are all tilapia.  What is going on?  I am absolutely stunned.  My wife asked "are you sure you stocked 24 and not 12?"  Really?  It is that weird.

Thanks for your input.  Anyone else have this happen to them?

[wes]

Humm what kind of system are you running??? Media bed only or DWT? Do you have a sump tank? I have had some of my fish end up in the sump tank.

[James Rubasch]

wes -

The tank in question is my 180 g. main tank.  The 110 g. sump has fry between 1-3 inches.  Sump pumps into the main tank, while the main tank drains by gravity to beds.  I have a drain cover over my drain, so no way fish could get out there.  I posted a video about my system earlier because of my unique alternating mechanism.  Here is that link: 

https://www.youtube.com/watch?v=bUh98WRjssQ&list=PLRbylB_6T4Llm...

Thanks,

Jim

[wes]

Well I took a look at you outside tank with cover on it. I will tell you those suckers will jump esp on a moon light night and if the sides aren't all tied down they will slip out the smallest opening. They could of jumped out at night and a coon, rat, or owl, or cat could of found them and ate them. That is just a thought. I haven't ever had any snakes get into my system so I am not sure if that could even be and issue. I do know this if they are dying in the tank the others will eat them all the way down to the bone and you wont even see the leftovers, most of the time.

[WaterFish22]

I have had fish get sucked in to my 350 canister filter. I found them in my over flow drains. I've had them even jump out of the tank.

This fish lived in one of my over flow drains for about 4 month before I realized where it went. Luckily, he survived  and is still alive today.

[James Rubasch]

Thanks for your responses.  I will improve my cover, and hopefully that will help.