[quote=”Teunis” post=2112] I was ordering some glass worms, and came up whit some questions… [/quote]
Glass worms (Chaoborus or Chorethra, “weiße Mückenlarven”) are a very good food for bigger grown and adult Paros. Fed by them, they reliably get fertile (which often could be a problem, especially if fed by Daphnia).
But I should point out that two good German breeders during the last years had severe problems with glassworms from the trade. One of them lost his complete stocks of more than ten species of Paros and many growing offspring. Among them were extremely valuable fish that he had caught himself at the original sites, so surely been determined as the species known from there. The other friend lost the majority of his whole stock and offspring. There are indications that much more people made that experience but up to the present day do not realize what happens, what the cause has been.
And what was the cause of that losses? Quite clearly and without any doubt a contamination of the commercially harvested and stored glassworms; in both cases there was a definite proof of this. One should especially be warned against those small plastic envelopes which are sold in thousands with mostly an unclear origin. The glassworms inside obviously are treated by a heavy poison to make them more stabile in that small containers. Often some die and to prevent the others from being infected those poisons are used. Often this works well, as it seems, but there can be most catastrophic results for the fish fed by them. At any rate if you cannot catch your glassworms yourself from the next fish-free pool (what is best) you should keep them for quite a time in a big container with much new water; best is to net them and give them without old polluted water into it.
Peter Finke