culling

[mpg]

i've dreaded asking this question for a while.

i have about a dozen zebra danio fry.  as they have gotten larger (they are now 6 weeks old and 3/8" long) it has become apparent that many of them have tails that don't seem to be developing properly.  their tails almost look like they have been broken at the tip.  viewed from the top the end of the tail makes a Z-shape.  it's not the whole bent spine, just the end of the tail.

does this sound like something that will work itself out?  or is this inbreeding at work?  should i begin culling the fry, or wait?

[luvfishies]

Sorry mpg, those fry will not develop normally. Time to cull. It's hard to do, but worth it to keep the strains healthy.

[mpg]

well... i did it.  (mostly)  very sad.  and feel like i need to confess my guilty feelings on the site.  

it's sacrificing the individuals for the sake of the group.  and better for everybody, right?  right?

[luvfishies]

Right

*pats mpg on the back, feeling sad also*

I had to do this on a regular basis as well when my kennyi male and crabro female would have "mutt" babies.

Terribly terribly hard to do, but it *should* be done. Thanks for making the right choice.

[colesea]

If you're gonna breed fish, the best thing I've found to do was to set up a seperate tank and nurture some sort of carnivore in it that would like to eat fry. It makes the deaths seem less "needless."  My favorite are tiny lionfish (a saltwater fish) although there are a number of predatory freshwater fish with small mouths (angels, discus) that wouldn't mind munching a few culled fry. Fish fry, especially those less than 48hrs are the healthiest thing to feed other fish because they still have the most nutrition in the form of their yolk sacs.
~~Colesea

[Vyache]

What is the best way to cull if you don't have a predatory fish? I've heard that if you put fish in the freezer with water their metabolizium will slow down as the water cools and they will die painlessly in their sleep. Any opinions out there?

[mpg]

what i did was put them in an icewater bath, then put that in the freezer to make sure.

they "pass out" pretty quickly in the ice water.  

i'm sure you could argue that freezing them from aquarium water temperature is more like going to sleep, and less cruel  as opposed to being shocked in the ice water.  

in my mind i wanted it to be over quickly.  it wasn't going to easy for me no matter which way.  the "blender" method is another instantaneous method, but my imagination figured out all kinds of things that could go wrong with that.

[luvfishies]

Clove oil.

I'ts used as an anaesthetic, and in massive doses it puts the fish to sleep, never to wake.

There are some other meds available from a vet, but most of us can get clove oil at the local health food store.

[theeyrietrainer]

yes, i agree with luvfishies. clove oil is the most humane method since it causes no pain for the fish. the fish just feel tired. another way to cull (i dont cull fish) is to have a small container (once big enough for it to swim around) feed the fish it's last meal and let the water deoxygenize itself. the fish will just get sleepy and suffocaty, and "sleep" although i wouldnt recommend any other culling methods besdies feeding or clove oil...

[wayne]

clove oil. I got a dwarf pike. I have a lot of hassle with inbred killies. I have asked some of the local killie experts and they thought inbreeding rather than a suboptimal diet for the fry.