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Hi all,

Just a quick querry for the more advanced out there. My understanding of breeding the plecos is very basic only but alot of them seem difficult. I work with a number of marine species that we are trying to breed and have found using some form of hormone manipulation to be beneficial.

For example if we have a fish that is obviously conditioned up and carrying oocytes that are large enough, depends on species and hormone of choice, we would then try some hormone manipulation with the males and/or females. We use products such as Human Choronic Gonadotrophin, pituitry extracts etc to achieve ovulation. If the fish is a little bit more reluctant we use a different horman such as LHRHa or GtH.

The hormone is either administered as a liquid to gain a rapid response or as a slow release inplant. I can see benefits to breeders using the inplants.

I know commercial breeders use it on a variety of ornamental species as well.

Has anyone tried it on some of there more reluctant breeders?

Adam

I really don't know much about this, but aren't horemones species specific? If not, how do you know which horemones would go with what fish? Also, how is it administered, added to water, or do you have to inject it? Also, what about price? (Sorry for all the questions, just interested in the subject

Almost all vertebrate hormones aren't species specific and can be used interchangeably. Because of the complex chemical nature of vertebrate hormones, the only way to effectively administer them is via injection.

The hormones aren't that species specific. Some hormone preperations work better with some fish than others. The more general hormones ie. those that are used to manufacture the final hormone work for more species than any other.

To choose the best hormone for a given situation you would need to consider what you are trying to achieve. Is it just ovulation? or do you want to enhance gamete production and then stimulate ovulation?

The most critical factor is the amount of hormone that you give to each fish. For example with the cod that I breed we have found that the ideal range is between 25-80ug/kg BW LHRHa. Below this figure we do not get a complete and reliable response. Above this range we get poor egg quality and low larval survival.

There are two methods of application. One is an aqueous injection into the muscle or into the body cavity. The other is a hormone inplant. The hormone is mixed in cholestoral or put into silastic tubing. The inplant is then placed under the skin of the fish generally in the muscle, very rarely into the body cavity, for obvious reasons.

The injection of the aqueous solution gives a very rapid rise and decrease in hormone levels. This is why it is usually associated with spawning of the fish. The inplant gives a gradual rise and prolonged elevated level of the hormones. This is usually associated with gamete formation and ovulation. The inplant generally lasts for one month but can be manufactured to last longer.

The cost may be prohibitive. The prices from an internet supplier is LHRHa 1mg US$37.50, HCG 10, 000IU US$45 ( http://www.argent-labs.com/)

Don't forget though that the amount that you will use on a 50g fish is very small. You may in fact find that storing the unused portion to be the biggest problem unless you have a number of fish to "manipulate."

Also a final word of caution, check your local laws about possesion of these hormones and there use.

I'm still waiting to hear of anyone using them.

Adam

Yes, they are used extensively by some commercial breeders, especially in the Czech Rep. and East Asia. The subject has been discussed extensively in these forums. Just run a search using the word "hormone".

While using hormones to breed endangered and difficult to breed species is a laudable and worthwhile goal, in practice, hormones have been used in a less than fully responsible way in the ornamental fish trade, and therefore have a bad reputation.

Dinyar

Dinyar,

I ran the search and there is a half dozen or more topics regarding the use of hormones. Most of the messages in these topics are about the misuse of these with sydontids in the eastern european countries in forming hybrids.

None of the posts have discussed the type of hormone, the stage at which it is administered, the dose, the imediate result and the larvae culture results. Also there is no mention of once the fish have been shown the "way" that they keep spawning. Biotype mimicing will always be the best method, but some species will need a helping hand.

This is the information I am searching for. I understand the ethics but still see it as a resonable approach for breeding catfish, particularly some of the L & LDAs.

The people who have been using these practises please provide some of the answers. I'm not looking for secrets but it would be interesting to know what has been tried and the results.

Adam

Adam wrote:None of the posts have discussed the type of hormone, the stage at which it is administered, the dose, the imediate result and the larvae culture results. Also there is no mention of once the fish have been shown the "way" that they keep spawning. Biotype mimicing will always be the best method, but some species will need a helping hand.

This is the information I am searching for. I understand the ethics but still see it as a resonable approach for breeding catfish, particularly some of the L & LDAs.

True, previous discussions on the subject of hormone-induced spawning have not addressed these issues, though if I recall correctly, questions along the lines of yours have been raised at least once before (by Charly Eon?). I too would be interested in learning more about this subject. And as I said before, I agree with you that hormone spawning can be a good thing if done responsibly.

Dinyar