Ant Posted December 13, 2004 Share Posted December 13, 2004 This is an issue that i have always wondered about. Can the water chemistry of the water affect the male/female ratio of fry? I have heard of the ph affecting some American dwarf species of cichlid but what about other species. In discussion with Kinerata, he stated that he thaught the sex of a fish is determined at fertilisation. Therefore if this is true can the eggs of fresh water fish (cichlids in particular) change sex when they are at this stage, as a result of water chemistry and or temperature? Anthony Link to comment Share on other sites More sharing options...
Ant Posted December 13, 2004 Author Share Posted December 13, 2004 oh forgot to mention. The reason i thaught of this question is that i had a relativly low ph with my lombardoi colony (7.2) and the temp was 26oc. About 90% of the fry were male. I thaught that maybe either the low ph or the low (relative) temperature produced more males. Anthony Link to comment Share on other sites More sharing options...
Mbuna Posted December 13, 2004 Share Posted December 13, 2004 this article is a great read about the effects of ph on fry sex ratios MCH article Link to comment Share on other sites More sharing options...
Ant Posted December 13, 2004 Author Share Posted December 13, 2004 Hmmm, intersting article. So this person is claiming that lower ph should should produce more females, due to the fact that the male sperm can not penetrate the egg in softer water, and male sperm is faster so when they can penetrate (when the water is harder) they do so in greater numbers (was his hypothesis based on another article). But given that my lombardoi colony (and hongi colony for that matter) that produced 90% males in water that according to his hypothesis should have a more female bias percentage maybe it wasn't the hardness or ph that created this change. Perhaps the whole change of conditions itself (not the chemical change) envoked the parent fish to somehow change there own percentage of male and female sperm* (playing the devils advocate here ). *i realise i've stated male and female sperm when infact it's just the difference of chromosones rather than the sperm have a different gender. I did this to make it more understandable. His arguement does show strongly that there is a correlation between ph/hardness and sex ratios of fry. I would like to know what other peoples thaughts and experiences are and maybe we can come up with a general answer. Even if the general answer is vauge and states that this is true in more cases than not. Anthony Link to comment Share on other sites More sharing options...
anchar Posted December 13, 2004 Share Posted December 13, 2004 Definately sex linked for kribensis merjo Link to comment Share on other sites More sharing options...
JiggyJigs Posted December 13, 2004 Share Posted December 13, 2004 Interesting read. Ive just started increasing the PH and hardness on my tanks gradually with a Rift Lake conditioner, will be interesting to see if it makes much difference. Dave Link to comment Share on other sites More sharing options...
Brett4Perth Posted December 13, 2004 Share Posted December 13, 2004 I don't think there is any doubt that water parameters affect sex ratios/ fertility/ etc in many if not most species of fish. I have yet to see any articles explaining the mechanism, mostly they just demonstrate that it happens. Can anyone help me out here?? Cheers Brett Link to comment Share on other sites More sharing options...
chorrylan Posted December 13, 2004 Share Posted December 13, 2004 hi, I think the answer is "yes, for some species" The piscean world appears to have a huge variation in terms of sexual determination and differentiation, having representatives for virtually every known and imagined model. There are examples such as kribensis that are affected by the pH levels, others such as the midas cichlid where sex determination appears to be largely that the bigger fish in any group 'become' males at ages between 6 and 24 months and even a very small number that follow the traditional mammalian model where sex is in the genes. I have found a few articles over the times as the subject (sex that is ) is mildly intruiging to me. I'll park some copies here: http://www.planetchan.com/laurie/pets/fish...nd_the_fishies/ for the next few weeks for anyone else interested. Be aware that the documents are large and I don't have a lot of bandwidth so don't download 'em unless you're particularly interested. Link to comment Share on other sites More sharing options...
Ant Posted December 13, 2004 Author Share Posted December 13, 2004 OK the Kribensis babies that i had turned out also about 80% males in ph of 6.8 and KH of about 3dh. does this fit with the general rule for kribensis? Thanks for the articles Laurie i will have a look through when i've got some spare time. I'm also interested in perhaps peoples waterparameters and around abouts what percentage of fry are male and female. This may demonstrate that within the cichlid species that this works as a general rule for most cichlid species. We may just find its for haps and mbuna malawi species (and those already discussed). Thanks Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.