Treating Ichthyobodo A.K.A. Costia

Lately I have been seeing a lot of concern for the disease/pathogen Costia. Because of this, I wanted to write a blog post about it that others could reference. Now I just want to make it perfecty clear I am not a vet, or a fish doctor, or have any prior background in the medical field, nor do I claim to know everything about everything, but, I do study Fish Medicine as a sub-hobby in addition to keeping fish as my main hobby.

Everything you read in this post is based off of research I have done in Medical Texts, online reputable resources, and personal experience. Some of the information might be useful to you, and I hope that it is.

Also, I hope I do not come off sounding like a complete idiot, I have a lot of thoughts and sometimes my mind trails off, so I did add a TL;DR section below. LOL. Enjoy!

Costia is a fish disease caused by an organism in the genus Ichthyobodo/Ichthyobodisais AKA Costia/Costiasis.

This parasite can only be seen using a scrape and scope with either a scrape of the gills, or the surface of the fish/ swab of the slime coat. This fish pathogen is a 5-10 micrometer flagellated protozoan parasite and is called both Ichthyobodo necator and Ichthyobodo pyriformis in scientific literature.

The pathogen is spread from one fish to another, making it a significant disease in fish aquaculture. In addition Costia has a very wide host range, including both salmonids and other fish species. It should be no surprise that juvenile fish are the most susceptible to this parasite. If one fish is affected, and there are multiple fish in the tank, its safe to assume they all have the pathogen, and should all be treated.

Common disease symptoms:
-Listlessness (common)
-Refusal of food
-General flashing behaviors and/or,
-Blue/gray film will appear on the surface of the fish (more advanced situations)

If the gills are infested, gill hyperplasia and lamellar fusion can be seen, as well as secondary fungal infections.

Ichthyobodo infection is not zoonotic and does not pose a threat to any human being. It's still best to wash your hands before and after you introduce them to any water with living animals in them, as to not spread additional bacteria from your hands, or to transmit the parasite to other tanks.

Icgthyobodo can survive in temperatures ranging from 36-degrees F to 84-degrees F. Gradually turning up the temperature in your aquarium to above 84-degrees F is a form of treatment. Sodium Chloride can be used at a gravity of 0.3%-0.5% can be an effective cure in it's self, however, if you have been treating it for a while using just salt, there is a chance that it will not be effective at all because the parasite can become salt resistant. Most fish keepers will usually avoid this method because there is a chance that it will not work, and it just weakens the fish in the long run with the ongoing illness present.

There are other methods, however. In addition to warming the water, Malachite Green, and Formalin are essential ingredients when treating this parasite. Popular medications include Pro-Form C, Chloramine- T, Kordon Rid Ich Plus, OR Hikari Ich-X because of their active ingredients.

If the fish in question are affected in their 'main' tank, with filters, substrate, decorations, and plants. If you remove the fish to be treated for the recommended 3-days, the Costia parasite usually dies in 24 hours without a host. But, since you are treating in a clean tank for the minimum of 3 days, it should die in everything on the main tank. (i.e. substrate, filters, bio-media, decorations etc…) just preform a water change as usual before returning the fish to their man tank after treatment.

Green Note: Me personally, if treating ANY parasite has been a long ongoing thing, I usually use clean, and sanitize EVERYTHING well, and re-cycle the tank. Medications cost a lot of money, and I don’t want to be wasting it for not being too careful and just doing things the 'easy way'. On top of that, I can not say for sure, but I think the longer a parasite is exposed to something (i.e. a medication) I feel like it could build up a resistance to the medication that you are using. I can't say for sure, but, if a strain of a parasite can become resistant to sodium chloride (NaCl), who is to say that it couldn’t happen to anything else?

A preventative measure to keeping Costia away can be taken by using KoiZyme. The only downside to using this medication is that it must be refrigerated.

TL;DR:

-Remove fish and put into a clean QT tank.
-Gradually raise water temperature to above 84-degrees F.
-Prep for treatment by doing daily water changes for up to 1-2 days. (i.e. Day 1: put fish into a clean QT tank with fresh clean water [nothing added except de-chlorinator]. Day 2 [next day - optional]: Change out the water again and let rest with fish still inside. Day 3: start treatment.)
-Treat with ONE of these medications: (CHOOSE ONE MEDICATION, NOT ALL OF THEM AT ONCE. THESE MEDICATION WILL KILL YOUR FISH IF YOU OVERDOSE.)
--Pro-Form C
--Chloramine T
--Kordon Rid Ich Plus
--Hikari Ich X

Green Note: I personally like to dilute the medication using the tank water first in a cup/jar or something and slowly add the medication/water mixture gradually throughout the day or over the course of several hours. I do not like to use medications often, but, I am a strong believer in adding the medication gradually over the course of several hours is safer then adding all the medication at once since medication is toxic to fish.