Dero Dero Dear!

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There may be those here who co-existed with me in Another Place and who may remember that I had a go at culturing Dero worms.

Well, the culture grew everso slowly until it began eventually to dwindle. The culprits, I'm more or less certain, were Ostracods. They would have competed with the worms for food, bred much faster and may well have predated the worms directly.

I rescued a few worms, then assiduously cleaned out their tank. I didn't use any chemicals ; rather, repeated washings and filter-sponge-squeezings until I figured I must have got rid of at least the vast majority of Ostracods. I then put the few worms back.

The worms have multiplied very much faster than during my previous attempt and I now have several lumps of them …
PhoenixWorms.jpg
However, unfortunately the Ostracods are back  (they're the little white dots) …
LittleBleeders.jpg
I could rinse-and-repeat the previous cleaning process ad infinitum, I suppose, but really would like to find a more permanent solution. So the purpose of this thread is to ask if anyone has any good ideas that I could use. 


In the interim I have put some Ostracods into some peat-infused water from my water-change butt.  It's at pH4.14 and has a conductivity of 21.6μS (microsiemens). In theory, the little bleeders shouldn't be able to tolerate those conditions for very long (they have shells for starters) and the only thought I have at the moment is to try to find a pH at which they croak but at which the worms may survive.

Any other thoughts are really most welcome!
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So, this may well not be feasible (and I don't know about the culturing of these creatures), but if the ostracod are free swimming and the worms stay in clusters on the bottom, is it possible to use some egg crate or something to protect the worms from being eaten, and then have a couple of ostracod eating fish go on an all you can eat holiday in the tank?
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Could this be an excuse for a betta? You'd need mesh over the egg crate to stop fish diving in for the worms.
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Enjoy your fish, shrimps and snails!
Ian
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Thanks everso for that, S.

I've tried a vaguely similar strategy before : I'd read that guppies may eat Hydra, so I borrowed three from #1 LFS to see if they'd deal with an infestation. They weren't at all interested in helping!

However, Ostracods would present a completely different temptation.  Yes, without a barrier the worms undoubtedly would get eaten simultaneously, or even preferentially. The worms do swim about to a certain extent, in search of food, and they're very tiny - adults about three or four times as big as a microworm, say. Baby Ostracods are very tiny, too, so to separate everything successfully the barrier's mesh would have to be (I'm guessing) around 25 microns max. And there'd have to be a way to remove all Ostracods from below the barrier first, I suppose. 

I wonder if I could remove as many worms as poss to a temporary container, move some fish in for your buffet feast and then reverse the process. It wouldn't be too much of a hassle to repeat a couple of times if necessary (I'm sure it would be necessary because of the presence of 'cod eggs) ; any more times than that and I might be getting worried about losing too great a proportion of the worm population.  

Incidentally, the 'cods that were set the task of drinking a pint of pH4 water last evening are still swimming around - so that method doesn't look too promising!


[Edit: to acknowledge P's interposed post]
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Bloomin' acid lovers!..............................
If at first you don't succeed....
...get someone else to do it! :D

Enjoy your fish, shrimps and snails!
Ian
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A few minutes ago I saw a few worms swimming around so I rushed off to get my camera. Of course when I returned they were gone!

However I did take a photo(ish) of one of the piles of worms. It's worse than I thought : the little green dots that you may be able to make out are 'cods …

Scrum.jpg
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That's a real shame, they're obviously determined. :(
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Indeed!

Clearly I have to do something quick-smart about separating the 'cods from the worm piles : a bit like shedding sheep, I suppose!

Using a microscope I felt wouldn't be suitable - the smallest magnification is x40 which would be OTT, and anyway the heat from the light would be too much given the time it's likely to take me. My magnifying glass is one that came out of a Christmas cracker and isn't really suitable. So I've ordered myself a better one. It'll arrive tomorrow, but I can make some sort of start today.

 I've made myself an operating table with a two-volume dictionary, an LED aquarium light, a couple of tupperware lids as diffusers, and a couple of glass bowls (pics later). For magnification I'm going to use a couple of the macro lenses from my camera and I'm going to try to remove most of the bigger 'cods individually with a small pipette. It's an all-day job, I think, with SpecSavers on speed-dial. Hopefully if I repeat the exercise tomorrow I may expect reasonable success.
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It's going better than I'd expected. I've done two little worm piles so far and have separated out thousands (literally) of 'cods from them.

The Heath-Robinson light box that I put together shows up the little blighters in silhouette and I can suck out dozens at a time with the pipette. Pouring more water onto a worm pile flushes more out, and so on. I only need to use the lens for the last couple of flushes, and for a final poke (with the end of the pipette) of the pile.
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Phase 1 complete! Here are some pics …


The operating theatre :
Theatre.jpg
A couple of worms doing freestyle :
FreeWiggly.jpg
One or two of the piles now largely 'cod-free (I won't have got 100% of them I don't think) ; and a closer look at a pile :
Decontaminated1.jpg
           
Decontaminated2.jpg

Next stage is to do some water-changes and then move some hungry fish in with the 'cods. I'm going to use 'Improbabiity Fish' (for those who remember what they are!)
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