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Are vinegar eels useful as food for smal fry?

Started by Guest_ignatz_* , Mar 13 2012 12:34 AM

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12 replies to this topic

#1 Guest_ignatz_*

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Posted 13 March 2012 - 12:34 AM

I have a bunch of E. zonatum fry that I'm doting over now. They're tiny little things, smallest fry that I've ever had to deal with, and they're feeding well on BBS. However, and interesting to me at least, they totally reject vinegar eels. At first they wouldn't even approach them, now I’ve observed them trying to ingest them and then quickly spitting them out. I’m wondering about the value of these little nematodes if they’re that unpalatable. Has anybody else found these to not be the great "emergency food" that they're often referred to as?

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#2 Guest_EricaWieser_*

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Posted 13 March 2012 - 06:52 AM

Maybe they taste bad? I've heard other people say that their Elassoma fry don't like microworms, while mine absolutely gobble them up as fast as they can. It's possible that the tiny worms have different flavors depending on what they're cultured on. I grow my microworms on oatmeal or slices of bread, with a little bit of yeast added so they don't smell bad.

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#3 Guest_VicC_*

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Posted 13 March 2012 - 12:38 PM

Microworms for bottom feeding fry.
Vinegar eels for mid-water or top feeding fry.

I use vinegar eels with great success with minnows.

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#4 Guest_gerald_*

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Posted 13 March 2012 - 01:33 PM

I've had similar results -- only the least fussy fish species like minnows, livebearers, and tetras will eat vinegar eels, but many other fish wont. I dont bother with them anymore. Has anybody here succesfully fed vinegar eels to darters, enneacanthus, elassoma, or other "picky" fry? (meaning they ate enough to make their bellies look full and round)? To me Elassoma are at the top of the picky-eaters list.

Microworms (including banana- and walter-worms) seem to be palatable to more species than vinegar eels are, but not to all fish. I suspect Erica's right about the growing media affecting their taste. If anybody has info on how to grow better-tasting micrworms (or fry acceptance & growth trials using worms grown on different media), please share. Fresh-hatched Artemia is probably the most widely-accepted food once the fry are big enough.

I now have a culture of Harpacticoid (i think ?) copepods that showed up in one of my rotifer jars. They are really small, benthic, and look like they should be good food. Will let you all know if they work out as well as I'm hoping.

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#5 Guest_EricaWieser_*

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Posted 13 March 2012 - 01:41 PM

To me Elassoma are at the top of the picky-eaters list.

I agree.

If anybody has info on how to grow better-tasting micrworms (or fry acceptance & growth trials using worms grown on different media), please share.

I'm not sure if it helps the fish eat them or not, but the worms smell much better to me at least when co-cultured with yeast. I add a generous sprinkling when I start every microworm culture. The yeast makes it smell like baking bread instead of nasty worms.

Palatability is a very interesting topic to me because right now I have some Elassoma gilberti that are rejecting the grindal worms. It's completely crazy to me, but there is a small percentage of the fish who will full on stare at a wiggling worm and either not strike at it or not swallow it. I accepted the fact that a small percentage of the population would starve when I was weaning the Elassoma onto flake food, but the continuation of the one or two stragglers who are still, despite tons of food, skinny, confuses me. Maybe the grindals taste bad. But the skinny ones aren't eating Ken's Pearls or the thawed bloodworms, either. I probably should also culture blackworms, the one thing so far that all of them have loved to eat. Grr. But I wish they would all just eat the grindal worms. Edit: Oh, for clarification, I'm talking about one to three fish out of fifty not eating the grindal worms. It's a much much much smaller fraction than wasn't eating the crushed fish flakes.

Edited by EricaWieser, 13 March 2012 - 01:49 PM.

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#6 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 13 March 2012 - 02:07 PM

I suspect Erica's right about the growing media affecting their taste. If anybody has info on how to grow better-tasting micrworms (or fry acceptance & growth trials using worms grown on different media), please share.

I am just speculating, but you know how they say that garlic is an appetite enhancer or whatever... wonder if you could mix garlic with the food and make your own garlic enriched foods...???

Either write something worth reading or do something worth writing. - Benjamin Franklin

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#7 Guest_EricaWieser_*

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Posted 13 March 2012 - 02:10 PM

I am just speculating, but you know how they say that garlic is an appetite enhancer or whatever... wonder if you could mix garlic with the food and make your own garlic enriched foods...???

I tried mixing garlic and Ken's Premium Golden Pearls a few weeks ago and it didn't work out so well. The garlic liquid turned the fish food into mush, which dried into super hard mush. Then after breaking it up it sank immediately and the fish didn't get a chance to eat it.

The grindal worms I culture are fed Kibbles 'N Bits. I'll try setting a piece of garlic on their sponge like it was a kibble and see what they do. Mebbe they'll eat it.

For the microworms I supposed one could easily add garlic by sprinkling a tad bit of garlic powder on the culture. The fry always eat the microworms, though, so it'd be hard to compare a result of "completely eaten" to "completely eaten."

Edited by EricaWieser, 13 March 2012 - 02:16 PM.

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#8 Guest_ignatz_*

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Posted 13 March 2012 - 06:03 PM

Very interesting responses. One of the things that I would like to do is to start maintaining some rotifer cultures, particularly the larger free swimming species (there's some literature out there that indicates that many of the sessile colonial species produce steroids and other nasties to make themselves unpalatable to fish. Also interested in the culture of small copepods. If anybody would like to send me some starters, I'd be happy to share some of my new cultures with them later on. As an out of work conservation biologist, I'm looking at a lot of time on my hands this summer.

Watching these little Elassoma fry makes me wonder if they're copepod specialists, which might make sense given where they breed. Wouldn't seem to me that it'd pay in evolutionary terms to be so damn picky when you're living in a weedy ditch, but maybe there's something else going on. Given that copepods are intermediary hosts to lots of helminths wouldn't support anything I can think of...
As for vinegar eels, I may keep a jar or two of them around but from here on out I'm not going to put any effort into keeping them going. I would imagine that they either taste like vinegar or have a yucky tasting cuticle on the outside to protect them from their acidic environment. I also have a hard time keeping the vinegar out of the tank - the coffee filter thing doesn't work for me for some reason.

Edited by ignatz, 13 March 2012 - 06:04 PM.

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#9 Guest_EricaWieser_*

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Posted 13 March 2012 - 07:04 PM

Watching these little Elassoma fry makes me wonder if they're copepod specialists, which might make sense given where they breed. Wouldn't seem to me that it'd pay in evolutionary terms to be so damn picky when you're living in a weedy ditch, but maybe there's something else going on. Given that copepods are intermediary hosts to lots of helminths wouldn't support anything I can think of...

There is more information at Barney, R. L., and Anson, B. J. 1920. Life History and Ecology of the Pygmy Sunfish, Elassoma Zonatum. Ecology 1:241-256.
To quote the wikipedia paragraph about their work,
"Stomach contents of 46 individual banded pygmy sunfish (26 of which were spawning adults) collected at Mound, Louisiana were examined for food identification by Barney and Anson. The main food identified at Mound included insect larvae (mostly from the family Chironomidae), small crustaceans and snail eggs. The crustaceans and snail eggs combined constituted the majority of the content. Next in quantity was the insect larva. It is also noted that minute amounts of algal spores were ingested by these fish. It is most likely that these algal blooms were taken in accidentally with other prey."

They do eat a lot of 'small crustaceans', but also love their insect larvae. And it's very easy to get them to eat worms. I mentioned that I feed them grindal worms; the vast majority of the Elassoma in my tank go crazy for them. They'll even, once they've learned that my face means worms now, beg for them.

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#10 Guest_ignatz_*

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Posted 13 March 2012 - 08:43 PM

I guess they like chironomid midge larvae as long as they're alive. Mine didn't even look at the frozen ones. Blackworms they liked. I'm wondering more about what the fry are oriented towards eating rather than the adults. At what size did they start taking the grindal worms?

I'm starting back on growing "micro" worms again - I gave up previously because I got sick of the smell, and the maintenance. But now that I'm also tired of messing with daphnia and their population swings I have to go back to other live foods. Thus the interest in relatively large species of rotifers.

One question - anybody have any tricks in harvesting enough micro worms to feed large number of fish without introducing their growing media into the tank? In established cultures getting some of the wet nasty semi-digested slime into the tank (and yeah, maybe I need to start new cultures more often) and in fry tanks it seems to contribute to pollution problems.

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#11 Guest_EricaWieser_*

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Posted 13 March 2012 - 09:02 PM

At what size did they start taking the grindal worms?

Uuuuummm? A half inch? A quarter? The juvenile grindal worms are smaller than the adults, so the itty bitty Elassoma eat the smaller grindals first.

I'm starting back on growing "micro" worms again - I gave up previously because I got sick of the smell, and the maintenance.

Yeast makes it smell like baking bread.

One question - anybody have any tricks in harvesting enough micro worms to feed large number of fish without introducing their growing media into the tank?

Lay a coffee filter on top of the surface of the media.
For example, I use oatmeal. I microwave the oatmeal with water for a minute or two then let it completely cool down. Then I put the oatmeal in the microworm tupperware, sprinkle some yeast, smear worms over the top, and add a coffee filter. I rip the coffee filter in half; half on the surface of the culture, half under the lid to prevent flies from going in and out through the air holes.

Where I got the idea: http://www.waynesthi.../microworms.htm

...maybe I need to start new cultures more often...

I find that a week is really the optimal lifespan for the cultures I keep. Two weeks is pushing it. Three weeks and you've got some worms remaining, but not enough to feed the fish. I keep three tupperwares and in general clean out the oldest, nastiest one once a week and rotate them through. That seems to work pretty well. Of course, as we speak two of my cultures are only one day old because I waited too long and two of them got gross. The third one repopulated those two. Having multiple cultures is nice 'cause they usually don't all crash at the same time, so when one does crash you just clean it and repopulate it from the fresher culture.

Edited by EricaWieser, 13 March 2012 - 09:04 PM.

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#12 Guest_ignatz_*

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Posted 13 March 2012 - 09:20 PM

Erica - thanks for the tip. I tried oatmeal here but never got a lot out of them - I think it's because of the consistently dry air that the cultures don't do as well as if I use oat or rice baby cereal. But when this stuff gets nasty, it gets NASTY. I'll try a compromise and maybe get the quick oats and make it a bit more runny, and will try the coffee filter method.

Edited by ignatz, 13 March 2012 - 09:20 PM.

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#13 Guest_gerald_*

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Posted 14 March 2012 - 03:43 PM

Give me your address and I'll send you Philodina rotifer/protozoa mix, my Harpacticoid-looking things, and Moina starter cultures.

Anybody have info comparing the different strains/species of micro-worms (banana-, walter-, etc) in terms of fish-acceptance or nutrition ?
I've read online that "standard" microworms are largest, banana-worms are a little smaller, and walter-worms the smallest, but haven't seen anything comparing their usefulness for first-feeding fry.