Vinegar eels *too* wiggly?

[Hobbit]

On @Fish Folk’s recommendation, I got myself a vinegar eel culture to help feed my tiny tiny honey gourami fry.

I thought this was a great plan! They’re super easy to keep and definitely tiny.

The problem is I’ve never seen one of the fry eat them. 🤦🏼‍♀️

I’m 95% sure the fry are big enough that they could eat them, but they seem to be put off. They don’t even try to go after them, though they will turn and watch it for a bit when one goes by.

I’m not sure if the worms are too wiggly for them? Is that even possible?

The other possibility is that the fry perceive the eels as too long to fit in their mouths. “Too long” isn’t a category that seem to exist for my tetras, who I’ve seen down mosquito larvae and VibraBites half the length of their bodies. But I know (and continue to learn) that honey fry are super picky. 

Is there any way I can test at least the first of these theories by slowing down the eels? If I put them in the fridge, I’m afraid they’ll just perk up as soon as they hit the warm water. What if I let them sit in tap water overnight? Would they half-die and slow down?

Just spitballing here. Any ideas are appreciated!

[Fish Folk]

32 minutes ago, Hobbit said:

On @Fish Folk’s recommendation, I got myself a vinegar eel culture to help feed my tiny tiny honey gourami fry.

I thought this was a great plan! They’re super easy to keep and definitely tiny.

The problem is I’ve never seen one of the fry eat them. 🤦🏼‍♀️

I’m 95% sure the fry are big enough that they could eat them, but they seem to be put off. They don’t even try to go after them, though they will turn and watch it for a bit when one goes by.

I’m not sure if the worms are too wiggly for them? Is that even possible?

The other possibility is that the fry perceive the eels as too long to fit in their mouths. “Too long” isn’t a category that seem to exist for my tetras, who I’ve seen down mosquito larvae and VibraBites half the length of their bodies. But I know (and continue to learn) that honey fry are super picky. 

Is there any way I can test at least the first of these theories by slowing down the eels? If I put them in the fridge, I’m afraid they’ll just perk up as soon as they hit the warm water. What if I let them sit in tap water overnight? Would they half-die and slow down?

Just spitballing here. Any ideas are appreciated!

Huh! Interesting. It would be fascinating to see a video of this. I know it's nearly impossible to get a camera to focus on eels + tiny gourami fry.

One thing some guys in our fish club do for teenie tiny fry is feed from sponge filter squeezings. The idea, as I understand it, is to squeeze out a sponge filter -- first into one container of tank water to get the large debris out, and then squeeze out again in another container of tank water. Allow things to settle, and then draw out some to feed from the upper-water-column (i.e. not the molm at the bottom). This should have ample infusoria in for tiny fry. You might try checking under a microscope to confirm.

Another trick some people try is to hard-boil an egg, and then take an extremely tiny dot of _yolk_ and mix that into a cup of tank water, and feed to fry. You must be so careful not to foul the water. Egg yolk feedings must be extremely sparing. Think pinhead sized hard-boiled egg yolk.

Just musing here . . . are you using baking soda to get the acid (vinegar) settled out before feeding the vinegar eels? Is it possible that the fry are being off-put by the acid rather than the eels themselves?

Here's an example of how we do it with our Killifish fry . . .

 

Edited May 18, 2021 by Fish Folk

[Hobbit]

@Fish Folk I’ll try to get a video tomorrow morning. Maybe if they know I’m calling them out on the forum, they’ll eat some!

I’m not neutralizing the acid, but I’ve watched the fry for maybe 10 minutes one time and I’d assume the acid would have disapated by then. Maybe not though. I’ll definitely try neutralizing the solution and see if it helps.

As far as the egg yolk... I know they won’t eat spirulina powder or other powdered fish food. I’ve tried that before. They won’t even try it if it’s not moving. Won’t even taste it and spit it out. So I’m doubtful about the yolk, unfortunately. Why do I have the problem children?? 😆

I can definitely do the sponge filter trick though! There’s always plenty of gunk in the filter from my 55 gallon.

The infusoria cultures I make with lettuce and tank water work for now, but I’d love to make these eels work. They’re just so easy to keep!

Thanks for the ideas!

[Lowells Fish Lab]

2 hours ago, Hobbit said:

The other possibility is that the fry perceive the eels as too long to fit in their mouths. 

I think you're right. I've seen plenty of small fry consider but then decide against eating vinegar eels. I figure they do a little fish math and conclude its more than they want to tangle with. It doesn't mean they won't eat them later, just not today. There are some really great fry powders available and paramecium cultures if you want to go down that rabbit hole.

[Hobbit]

5 hours ago, Lowells Fish Lab said:

There are some really great fry powders available and paramecium cultures if you want to go down that rabbit hole.

Thanks @Lowells Fish Lab. They won’t eat powders, unfortunately. Maybe there’s a way to keep a paramecium culture for more than a week? I think long-term I may want to get a green water tank/bowl up and running like @H20CultureLabs . The question is: would my husband think that’s more gross or less gross than jars of decaying lettuce? 🤔

[H20CultureLabs]

@HobbitAll good ideas! Instead of jars of decaying lettuce, rabbit food pellets (which are mostly alfa-alfa) work well as a green-water/infusoria food source. May be more palatable than a jar of decaying lettuce. My greenwater "jugs" can be found at Walmart for $6.

I personally love the idea of sponge-filter "squeezing" to feed the tiniest fry. Bombarding them with a diverse range of foods like this is a great way to feed fry of all sizes. Thats what saltwater breeders working with planktonic fry do. If you have a local LFS or breeder, ask for a bag of sponge filter/mechanical filter squeeze; they are usually happy to give you some.

Keeping "pure" cultures of anything is difficult but polycultures are easier. I keep a jar of greenwater that I place seed-shrimp, daphnia, copepods, and any other interesting small critter I can suck out with a syringe; the strongest critters survive and then get fed back to the fish. It also acts as a great aquarium/pond inoculation culture.

[Hobbit]

Alright! I have done some filming and here’s what I have to report.

First, it’s probably relevant to know that I only have two fry right now, and yesterday they had their first meal of bbs. So they’re not tiny enough anymore to need a transition food. But of course, I wanted to see if they would still ignore the eels.

Mostly they did indeed ignore them.

In the video below you can see the fry munching something on the wall. There are these tiny slug-like things all over the acrylic that move very slowly, and the fry are constantly picking them off the glass and then spitting them back out. Note the wiggly eel just below the fry, completely ignored:

Last night I went ahead and put some eels in the fridge with a pinch of baking soda. It turns out the cold does slow the eels down, but just as I figured, they picked up probably 75% of their speed when they hit the warm water. The fry were still ignoring them.

 

But then... 😀😀😀😀

You can see the fry try to eat the first eel but fail. That in itself was something I’d never seen before. And then it just goes and noms the second one like a pro.

Maybe they just needed practice!

If it takes them some time to get the hang of eating these, it won’t really work as a transition food. But it’s good to have something to feed them in a pinch when I’m between brine shrimp hatches!

In other good news, my hubby said green water would be “fine,” though he didn’t confirm whether it would be less gross. I think the answer is yes, but I didn’t want to push it. 😄

Edited May 19, 2021 by Hobbit
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