PlanetCatfish.com

hi all,
Can someone explain to me the reason for scaleless fish being (considered) sensitive to medication?

If you have no scales, there is that much more surface area of exposed skin through which chemicals can be absorbed.

That makes sense. What about armored catfishes? Do their bony plates provide the same degree of protection as scales in other fish?

They should. But quite a number of ostariophysans are sensitive to medication. Must be either be all the taste buds they have, or their physiological reaction to schreckstoff.

Are catfish as sensitive to schreckstoff as cyprinids?

All ostariophysans react one way or another to schreckstoff. Producing schreckstoff in specialized epidermal cells is a unique feature of ostariophysans.

will Mastacembelids be affected by sterazin? i know they aren't scaleless, but many websites report that they are sensitive to medication, although this may be because they believe them to be scaleless.

could anyone help me with this, as i may have to treat the tank for gill flukes.

thanks.

All ostariophysans react one way or another to schreckstoff. Producing schreckstoff in specialized epidermal cells is a unique feature of ostariophysans.

I understand the epidermal cell part (external layer, akin to skin). The other 2 parts leave me at sea. Can you please lend a hand in explaining what ostariophysans and schreckstoff mean? My dictionary doesn't have those words.

(Silurus, can you please recommend a dictionary or book of icthyology words/phrases? Thanks.)

Schreckstoff=alarm substance produced by fish when stressed. Something like pheromones (a word you should be able to find in a plain ol' dictionary).

Ostariophysans=a group of fishes that produce shreckstoff, have a swimbladder subdivided into two lobes and breeding tubercles. Divided into the Anotophysi (Gonorhynchiformes, best known example being the milkfish Chanos) and the Otophysi (comprising of barbs, tetras, catfishes and South American electric fishes). The Otophysi have a specialized auditory adaptation involving the swim bladder and the first few vertebrae.

but many websites report that they are sensitive to medication, although this may be because they believe them to be scaleless.

Mastacembelids have small scales partially embedded into the skin (like loaches). They can be thought of as being "semi-scaleless".

Thanks!

Time for a new dictionary, too!

will Mastacembelids be affected by sterazin? i know they aren't scaleless, but many websites report that they are sensitive to medication, although this may be because they believe them to be scaleless.

could anyone help me with this, as i may have to treat the tank for gill flukes.

If you're not entirely sure how a fish will react to a medication you could make up a seperate bath to put the fish in and observe it closely for a couple of hours but as soon as it shows any sign of distress remove it. This would save having to change a load of tank water if the fish is sensitive. Having said that some fish can take a day or so to show the effects of being sensitive to a particular medication, a good sized water change solves that.

I once put medication in a community tank with Khulie Loaches and they went absolutely mental as only a Khulie Loach can... and I thought I'd killed them. They are virtually impossible to catch in my tank and eventually burried themselves in the substrate, when it came to feeding time several hours later they were out and about as normal much to my relief. I think the problem was that when the medication went in it was at it's most potent and was stinging a bit, as the medication broke down the Khulies were able to tolerate it, which is probably one of the reasons why some manufacturers recommend half dosage for scaleless fish.

The other thing I would recommend is a UV sterilser, great for fish sensitive to medications as they kill a load of pathogens in the water column of the tank, the medicated bath would kill anything on the fish so in all it makes things less stressful. I'm in the process of putting them on all my tanks and wish I'd done it sooner.