Anorexic Bombina tadpoles

[francesco]

I've noticed that when keeping several tadpoles together most of them go anorexic and die whilst 2-3 continue to grow normally. This didn't happen when I left them with the parents.
Has this happened to anyone else? What could be the reason?

[alan]

What volume of water are they in and what/how much are you feeding them?

I've just raised ~25 B.orientalis tadpoles in ~20 litres of water with no problems:
http://www.caudata.org/forum/messages/7618/36086.html

[francesco]

I had 10 with their parents which were all right. The adults are kept in a aquarium (40cm X 25cm) with water 4cm deep.
The anorexic ones were kept in an other aquarium slightly bigger with much more water (20 cm deep).
I didn't really feed them cos I put plenty of elodea and algae for them to eat.
They are b. variegata and pachypus.

[francesco]

couldn't it be that if you put too many together the fittest produce some kind of hormone that inhibits the growth of the others? Maybe because in the wild bombina can lay eggs even in puddles made by the cars this could be a mechanism to ensure that out of 20 tadpoles at least a few can reach metamorphosis faster than the rest...

[alan]

Feed 'em! (but don't overdo it).

[caleb]

Larger Bombina tadpoles have been shown to inhibit the growth of smaller ones. A micro-organism in their faeces was thought to be responsible.

Frequent water changes will probably help. You might also want to separate out any that grow faster than the others.

I'd agree with Alan though, they will need some extra food other than elodea and algae.

[han]

Try to keep them cool. Change water/clean tanks or containers every day.Feed them vegetable (flakes for tropical fish, spirulina, yeast flakes) and animal food (frozen/dried daphnia, bloodworms). Good luck!
Han.

[michael]

I have best experiences by feeding dried (microwave!) Taraxacum officinale or Urtica dioica leaves.
They do not pollute the water (like fish pellets) if given in too high quantities and make the larvae grow very well.

The problem in keeping many tadpoles together usually is the "crowding-effect".
The strongest ones will produce hormones that make the other ones stop growing. This is quite useful in wilderness due to limited food resurces.

My suggestion is to give the tadpoles more space besides the food quantity. My B. variegata usually have 1 ltr per tadpole miniumum and grow very well.

Cheers
Michael