Reptile & Amphibian Forums

Skiploader and others have cautioned us as to the presence of thiaminase (an enzyme that breaks down thiamine and Vit B1 in frozen fish)in herring and other fish. Doug T. and I have used salt water fish in moderation over the years without known problems...

http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm

I thought this was a concise article on this often discussed yet little understood topic. Having fed my Drys, especially neonates, quite a few gold fish and minnows, blue gills and bass, I am concerned. However, like so many things, moderation in all things applies. Usually I just get them started feeding on fish, then quickly convert to a varied diet of birds, mammals and the occasional frog, fish, snake, etc. I am unaware of any deleterious effects to my Drys as a result of feeding a few fish. Variety is key. Also, North American sunfishes (Centrarchids) are said to be near free of thiaminase, so take a kid fishing and bring home some small bluegills, sunfish, fillet and feed if you need to get some stubborn Dry started...one of many ways apparently. Flat fish at the sea... Good luck, Vic

Salmon and trout are always good choices. I've never had a problem getting young drys to take trout or salmon fillets.

I did some research on silversides awhile back and discovered that only one brand of commercial frozen silversides were actual silversides (which are free of thiaminase).

The others were assorted baitfish and all contained thiaminase.

For example:

Hikari is using pseudohemiculter dispair which is a cyprinid (as are goldfish and other known carriers of thiaminase). My bet would be that they contain thiaminase - the rep even wrote back that they add thiamin to these fish to counteract thiaminase.

That's junk science and doesn't help - Hikari should know better. Hikari silversides are not silversides and should be avoided.

H20 Life Foods says that they use "blue anchovies" from Vietnam. These could be either engraulidae, stolephorus or cetengraulis. The fact that they can't tell me which species it is and the fact that they are - like Hikari - mislabeled as silversides is a big red flag.

Engraulidae are confirmed carriers of thiaminase. So H20 Life Foods also is a no - no.

OmegaSea uses Hemisalanx Prognathus Regan (Salanx Sp.) Hemisalanx are related to true smelts. Some smelts have thiaminase. Some do not.

There is nothing I can find verifying their claims that Salangidae are thiaminase free.

However, it is clear that these are also not true silversides.

SF Bay Brand was the only one I cold verify are selling true silversides (menidia menidia) free of thiaminase.

As you stated, Vic. Moderation is the key. I am a big proponent off rotating food items with my drys.

The problem is that some people get lazy and stick with one food type.

About two years ago I passed on a young male eastern indigo because the owner had never weaned it off of silversides.

One trick that has never failed me is to wrap a thawed rodent or quail chick in a whole trout overnight in the fridge. The "marinated" rodent has never been refused.

I've also had good luck scenting rodents with beaten egg.