Get rid of snails

[Trouser Cough]

That 'chemical communication' is why I (mostly) quit feeding fat head minnows to some of my other fish. After a stretch of observation you could see that as a group they were sensing something and reacting w/ what I might articulate as fear. Turns out though that it's tough to find a fish stupider than a fat head so I'm off the live food, mostly.

 

[Something Fishy Here]

Oh like the minnows were putting out the fear hormones and then the rest of the tank thought there was a predator nearby?

 

[Trouser Cough]

Oh like the minnows were putting out the fear hormones and then the rest of the tank thought there was a predator nearby?

I would normally buy fat heads in lots of 500 or so and it wasn't so much that I noticed anything else in the tank picking up on the the minnow's response but rather that all the minnows were clearly responding w/ some variant of fear. I'm far from a Nancy boy but there was something about that that seemed like I should avoid moving forward.

Long ago in a Cajun restaurant thousands of miles away from me there was a poster on the wall of a couple giant crawdads sitting down to a huge bowl of people. The caption underneath was an instruction from one crawdad saying something like "you pops dey head off, squeeze dey butt and suck out da juice'. I wouldn't have enjoyed that and it occurred to me that the minnows apparently weren't either.

 

[Midwater]

That 'chemical communication' ....

I regularly put a couple of thousand live tilapia feeders in my datnoid tank. The day they go in, they swim together in swarms, flowing in unison. Looks terrific. The next day, all that has changed, and there are a coupe of thousand (less a few hundred) all out for themselves. They have learnt. Whether chemical signals or not, they know. (And tilapia ain't stupid.)

 

[jjohnwm]

I regularly put a couple of thousand live tilapia feeders in my datnoid tank. The day they go in, they swim together in swarms, flowing in unison. Looks terrific. The next day, all that has changed, and there are a coupe of thousand (less a few hundred) all out for themselves. They have learnt. Whether chemical signals or not, they know. (And tilapia ain't stupid.)

But...if you threw a couple thousand Tilapia...or, for that, matter, Fatheads...into that big tank without any Datnoids or other predators...they'd do pretty much the same thing. They'd school tightly for a day or two, then relax and split up. Even swimming independently, the confines of an aquarium would keep them in close enough contact that they would be comfortable.

Fatheads may very well be the dumbest fish we keep...and Tilapia and other cichlids among the smartest. But the difference is still, relatively speaking, pretty small. They are fish; none of them are going to win scholarships to Harvard.

Say you toss a few feeders in a predator tank. A bunch get eaten immediately, while they are still zipping cluelessly around. The ones who survive a bit longer get to know the tank, start to relax, and no longer give off that "OHMYGODIAMLOSTANDCONFUSEDEATME!EATME!EATME!!" vibe; it takes a big more effort to catch and eat them. And then there's that one or two feeders that win the lottery and last long enough to know where to hide, who to avoid, and perhaps even how to recognize the "predator vibe" that identifies somebody who is seriously on the prowl for a meal. They will die last because they take the most effort and determination to catch...but, again, it's an aquarium and there is no way for them to get more than a couple feet away from all those mouths...it's only a matter of time.

A predator inevitably loses contest after contest with its prey before winning one and enjoying a meal. Prey only gets to lose once, and it is permanent. That's why you buy them by the thousand.