Tadpoles with crooked tails

[Gemma]

All of my tadpoles were doing fine, but tonight I noticed that one of the large ones and a medium sized one have crooked tails. They definitely weren't like that yesterday. They seem as lively as usual, but the larger one is swimming a tiny bit more clumsily than the other tadpoles. I remembered reading somewhere online of another person raising ACF tadpoles, and a lot of their tadpoles suddenly developed crooked tails. I think they put it down to something in the water.

I'm worried now that this might happen to the rest of the tadpoles, and about how it might affect their health and development. I don't know what's caused it. They have an air stone oxygenating the water, I change a third of their water every day, I always temperature match and condition new water, and I add/remove water from the tank gently so that I don't disturb them. I feed them 2-3 times per day on powdered reptomin. I keep the bottom of the tank clean. I always wash my hands and make sure that I rinse them thoroughly before I put them into the water. :/

Does anyone know what could have caused this, and how I can stop it from happening to the others? How are the 2 affected tadpoles likely to develop?

[Eric Walker]

I had two theloderma asperum tads suddenly develop a verticle bend in their tails about 2/3rds through development a few years ago. You can kind of see it on the picture. This was take as it was morphing about three weeks after i noticed it.They both developed just fine since they absorb their tail anyway. I was never quite sure why it happened and I haven't seen it since

[Eric Walker]

I had two theloderma asperum tads suddenly develop a verticle bend in their tails about 2/3rds through development a few years ago. You can kind of see it on the picture. This was taken as it was morphing about three weeks after i noticed it.They both developed just fine since they absorb their tail anyway. I was never quite sure why it happened and I haven't seen it since

[Geoff]

Does anyone know what could have caused this, and how I can stop it from happening to the others? How are the 2 affected tadpoles likely to develop?

It's always disappointing when something like this happens and I do sympathise with you. I experienced the same problem 16 years ago with X. borealis tadpoles. I cannot honestly remember what the eventual outcome was but I seem to think that some of the froglets had twisted spines. I bred the frogs again 8 years later expecting the same thing but on that occasion the problem I encountered was tadpoles with deformed forelimbs resembling "spindly leg syndrome" that breeders of poison dart frogs sometimes experience with their froglets.

I don't know what the cause is but I suspect that it might be related to a mineral deficiency in the water as I live in an area where the tap water is very soft (ie: low in Calcium and Magnesium). Below is a link to a paper about water hardness (GH), which concludes with "The common features of all the water sources evaluated that resulted in high survival and normal development of Xenopus embryos are a high concentration of calcium and a high GH value. Thus, we conclude that water hardness should be an important consideration in housing Xenopus females to be used for oocyte production." The article's a PDF document at: http://www.xenopus.com/Water_Hardness_final_proofs.pdf

[Gemma]

Thanks so much for the replies.

I didn't realise this was so common. I think 3 of the tadpoles might be like this but I'm not sure since they won't keep still, but at least 2 of them have bent tails. My affected tadpoles are about 2/3 through development too. It's a relief to know that in some cases they can develop normally. I'm praying they don't end up with twisted spines. Poor little things

Geoff, I hadn't thought about that as a possible cause. I don't have anything to test my water hardness with but I just found a website about water in my local area, put my postcode in and it told me that on average the water around here is very soft (10.8mg/l calcium, it said). I also suspect that it might be down to a mineral deficiency now. Thankfully most of the tadpoles seem fine and I have 10 seemingly healthy little froglets. I hope no more get affected.