MB and scaleless fish

[babygeige]

This is sort of 2 questions in one. I read on a website that cories are scaleless fish and that it is important to be careful as to what kinds of medicines are used in a tank that houses them. Is that correct? Are they scaleless? Neither of my books mention that.

And my other question is whether or not MB is safe for scaleless fish. I looked on Carl's site and he didn't say it wasn't, so I would think it's ok. I just wanted to check, because I recall using MB shells in my QT tank when I bought both batches of cories that I lost shortly afterwards. If MB isn't good for them, perhaps this is what caused all but 1 of them to die.

[Carl]

Methylene Blue is quite safe for all fish.

What Methylene Blue can harm is nitrifying bacteria (although diluted and used carefully it can be safe for this), the same goes for plants.

It is Malachite Green that is harmful to scaleless and other delicate fish, however even with Malachite Green newer formulations are better buffered and do not contain as much zinc (if any) which is what is so hard on these fish. Also low pH and lack of minerals makes Malachite Green much more dangerous.

As to the Corys you lost, this may have been a weak batch as although Medicated Wonder Shells contain Malachite Green, they have it at a lower dose than say Quick Cure (which is also why although they are a good product, they are not as strong for serious Ich infestations), but are best for mild and especially follow up or prevention. Another key point as to Medicated Wonder Shells is that they buffer the water lowering the toxic side effects of Malachite Green even more.
I have used the Med. WS for years with Cory Cats without a single issue provided the fish were not suffering from other problems which is unfortunately not un-commmon with these fish.

As for other Malachite Green products, I have found SeaChems Paraguard to be the best combination of effectiveness and safety when it comes to use with sensitive fish (Quick is excellent too and just as strong, if not maybe a little more effective, but is not as safe for sensitive fish).
Kordon's Rid Ich is probably the safest Ich remedy, but I have found it to be often very ineffective, so if safety is a concern I would recommend Kordon' Herbal Ich Attack or the Heat method instead.


Carl

[kagome]

Just a note about scaleless fish. Generally speaking, catfish and loaches do not have what are considered "true scales" and since there skin is bare they can be more sensitive to things like medication. Some catfish do have bony plates or free dermal plates, even these are not considered true scales. So it is true that your cories are scaleless, and unfortunately these fish are both more susceptible to contracting external parasites but also are more difficult to treat once they do have the parasites. I've been using the Med WS in my tank that has a clown loach and he's doing great. Some other common scaleless fish:

elephant nose
clown loach
zebra loach
yo yo loach
ghost knife
clown knife
and pretty much all the different catfish
I'm sure there's way more but all I could think of were these few off the top of my head.

[bikeguy33]

most scaless fish can handle half doses of meds for double the time with water changes. if they are strong they can survive it.....

[babygeige]

Ok, thanks for the answers everyone. I kind of thought MB was safe, since nothing says it wasn't. It was just an idea that popped into my head.

I am trying some peppered cories from a new lfs. Well, it looks like it's been there for a long time, but it's new to me. They didn't have a very large selection of fish, but the ones that they had seemed pretty healthy, so maybe I will have better luck with these.