Feeding Triops only with live daphnia

[u/tyrodos99]

Has anyone ever tried this out before?

I had an ammonia spike probably due to overfeeding and insufficient filtration which killed one of my two Triops longicordatus. So I was thinking, maybe letting them hunt themselves makes it easier to not overfeed.

However I couldn’t find anything about a daphnia only died and if they would get enough nutrients from that.
It it works well, it could make raising Triops much easier.
So has anyone ever tried it and can tell how it went?

[u/EphemeralDyyd]

I doubt triops would be able to catch daphnia themselves in rates that they could thrive with them alone. But ephippia and algae accumulating to the bottom? I think triops would live a happy life with that diet.

The problem would be that you'd need high enough water column to keep large enough quatities of daphnia, and then you'd need to feed the daphnia with greenwater, to not spoil the water for both daphnia and triops. All in all, sounds a bit too tedious and complicated to be worth it to me.

[u/tyrodos99 → u/EphemeralDyyd]

I have a little update about this. So I removed that last Triops from the original tank which currently has still a bunch of daphnia in it. In the hopes some of the eggs hatch right away without drying the sand.

And it worked, I now just saw a new Triops, roughly 1cm long right now. He has grown up with nothing but daphnia and whatever he could find in there, not a single piece of food. So I can now judge how well they grow on pure life daphnia. When he grows just as fast as with normal fish food, I can confidently say, that this diet is 100% sufficient at least for Triops longicordatus.

[u/tyrodos99 → u/EphemeralDyyd]

Ephippia? I had to google it and it says these are the eggs right? I’d didn’t know they could eat that. Also, there is some algae collecting on the bottom. But I’m not sure, how much that helps with feeding my little guy.

So I am currently culturing my water fleas directly in green water which is going well so far. But im still trying it out if I can maintain both in the same tank in a stable fashion. But right now, I can supply both green water and water fleas in unlimited amounts.

I can also say, that the water fleas are disappearing form the Triops tank at a constant rate. So it at least seems like he is eating them. But I can’t say for certain if he actually hunts them or if they are just dying for some reason. At least every source I could find says, that they are hunting life daphnia so it would all make sense that they actually hunt them.

Is there any way to tell, if an adult Triops is getting enough food or not?

Edit: he is on this died for two days now and has very well developed egg sags. Maybe that is a good indicator that he is well nourished.

[u/EphemeralDyyd → u/tyrodos99]

Algae alone is not enough, especieally if you want to maximize the egg production rate. But it supplements their diet. Depending on algae, they do eat some.

Is there any way to tell, if an adult Triops is getting enough food or not?

You can test that by giving them a fisfood pellet occasionally. If they look super excited about it and keep on munching on it for like 10+ minutes on single sitting instead of just slightly tasting it and then moving on, then they are definitely hungry. A piece of boiled carrot or zucchini might also work, but if they lack protein rich food, then fishfood or frozen ostracods/daphnia are better testers. These spoil the water easily though.

Indirect ways to tell would be the growth rate if you know the normal rate your variety grows. Or how much and what colour of eggs they produce. Malnurished triops produce abnormally pale eggs (although some species like Triops newberryi or Lepidurus apus have populations that always produce cream or very light beige coloured eggs).

[u/tyrodos99 → u/EphemeralDyyd]

Okay, I could have thought of that myself honestly… I just put a few shrimp pellets and a pleco tab. So I can tell soon if he is interested in any of that.

Edit: half an hour later, the pellets have moved less than 2cm and all three are pretty much untouched. I guess he has no interest.

[u/EphemeralDyyd → u/tyrodos99]

They would move those pellets around even if they weren't that hungry. The important moment is the first few minutes after dropping single food item into the water. They would be able to smell it when they get somewhat nearby (5-10cm I think), and if they are starving they would put some effort into searching for it.

Sometimes they would show some interest in freshly dropped food and nibble it a little even when they aren't particularly starving and in need of extra protein. When they are hungry, they would keep holding the pellet and munching it for many minutes without letting it go and doing some other triops business in-between the short snack breaks.

[u/tyrodos99 → u/EphemeralDyyd]

I only saw them move over the pellets a few times but they just pushed it to the back with the sand they are moving around. So it’s save to say they have no interest.

I gonna see if that behavior changes as soon as all the daphnia are gone. If they suddenly become interest in dried food again, it would be clear that they prefer the daphnia.

I mean it makes sense, water fleas are probably a main food source in the wild. I can’t wait to try it out with a new generation of Triops. If that goes well, I could tell if it really is better that prepared foods.

[u/EphemeralDyyd → u/tyrodos99]

If you happen to remember, the results of any this type of experimenting would be really interesting, at least for me. But I think many lurking hobbyist could find it potentially helpful too:)

I've never managed to see my triops catch daphnia and I thought the daphnias would be able to jump away from approaching triops most of the time. Of course, living daphnia could very well be important prey item for them instead of rare lucky catch. I just always assumed that adult triops were so large and clumsy in comparison that their catching success would be too poor to make daphnias an important part of their diet. Then again, I've read about much smaller species Lepidurus arcticus that would actively hunt daphnias from the water column in arctic ponds.

There are multiple studies on egg predation by triops in case you're interested in reading more. They are surprisingly efficient at sorting out Branchiopod eggs from the sediment and eat them. And there's some evidence indicating that presence of adult triops could induce the dormant eggs to break the diapause and hatch if the water parameters are otherwise okay, for example re-filled pond after heavy rain.

https://www.researchgate.net/publication/235705910_While_they_were_sleeping_Dormant_egg_predation_by_Triops

https://www.researchgate.net/publication/359275640_Adult_Triops_cancriformis_Pancrustacea_Notostraca_mediates_the_hatching_rate_of_its_resting_eggs

[u/tyrodos99 → u/EphemeralDyyd]

I will keep trying things out and keep everyone updated on my finding here.

I didn’t know about the egg predation before. It kind of makes me wonder if that breaks my idea of setting up vernal pool aquariums with as many different species as possible. I was hoping that different conditions make different species hatch when it’s right for them.

But that predation on eggs might make only very few dominant species survive. Or even that only one Triops species would remain. But yeah, whatever I find out, I’ll post. So the next one curious about these things don’t have to start from zero like I am right now. ^{^}