The dreaded "green fungus" Ellobiopsidae neocaridina shrimp parasite and how to cure it March 28 2017, 1 Comment

Many shrimpers have been seeing the appearance of a "green fungus" growing on the abdomen extending through the length of the swimmerets or pleopod of neocaridina shrimp.  It is often mistaken for a pregnant female carrying eggs by the unknowing hobbyist and this mistake often can result in a completely compromised neocaridina shrimp colony.  

In this write up I will discuss my research regarding the ellobiopsid class of parasite, its similarities to their marine version's family members and my experiments to cure my colony.  Before I continue I must make it clear that I've tried every method currently documented online without any success.  The current methodology is to use dips to disturb the protozoan parasite ranging from heavy salt dips (up to 2 tbs per cup RO water) to formalin mixes or fenbendazole (up to toxic levels).  These methods are standard practice to fix common shrimp hobbyist issues, ranging from the classic external parasites such as vorticella and scutariella japonica to hydra and planaria organisms.

 My research:  I found only a few accredited scientific sources explaining the characteristics of ellobiopsids and to my surprise I could only find information on the marine family of ellobiopsid protist.  However I did come across a very interesting article in the Journal of Eukaryotic Microbiology (51(2):246-52 · March 2004) that discussed the characteristics of this dreaded parasite family.  In summary, they concluded that ellobiopsids "possess a nutrient absorbing ‘root’ inside the host and reproductive structures that protrude through the carapace.  Ellobiopsids have variously been affiliated with fungi, ‘colorless algae’, and dinoflagellates".  As an amateur mycologist, I was intrigued by the mentioning of their relationship to fungi and that gave me a hint to the complete taxonomy of the freshwater ellobiopsids, from my interest in studying the relationship between the cordyceps parasitic fungi genus and insects.  For cordycept - insect relationships, their parasite life-cycle is extremely particular to a single species of insect because it evolves very specific mechanisms to completely dominate the particular host insect species.  The neocaridina - ellobiopsid relationship, is also similar in this way.  The ellobiopsid protist will not affect caridina shrimp, only neocaridina shrimp.  I have evidence of this, as I kept all of my culled shrimp in a single aquarium and only my neos (whom all were infected/compromised) would pop up with the fruiting stage of the infection.  Here is an illustration from the earlier journal article of the fruiting ellobiopsid protozoa.

 

I would like to point out that in said journal, they claim that the ellobiopsid has some kind of hooking mechanism that can penetrate the host's carapace to then feed on cellular nutrients, however I do not believe this is correct for the freshwater version since that would infer it would also spread to caridina shrimp, similar other common external parasites.

 

My observations:  Taking notice that my caridina culls were never visually infected by ellobiopsid, I started to wonder the true mechanism of the parasite.  As I kept raising my "healthy" neocaridina culls, more and more instances of ellobiopsid infection arose.  I kept hundreds of cull varieties in a 29 gallon tank, and I also underfed the tank to limit breeding and especially to avoid dirtying the water...Which I found out (from the Asian breeders that defend the quality of their sickened shrimp LOL) is one of the primary circumstances for the parasite to reveal its fruiting body on the weakened shrimp.  While I can not verify the exact trigger of the fruiting stage, I can share my observations that my shrimp will eat an infected shrimp's ellobiopsid parasite fruiting body first.  Here is a picture of my first colony of neocaridina and a dead shrimp (that became infected when I introduced another lineage of high grade bloody mary imported from Asia) and its abdomen eaten clean.  **Shout out to Eric Martens at DiscoBee.com for guiding me through my entrance into the hobby.  I'm sure you all have quite the sticker collection yourselves! ** 

 But I digress, this evidence started to give me an insight of the beginnings of this parasite's life-cycle.  If you are unfortunate enough to have seen this parasite in your colony you probably have caught it too late to the point where it has fully grown under the pleopod, severely disabling the mobility of the shrimp, if you happen to look closely you will also see that the ellobiopsid protozoan fruiting body is often loosely attached at the most mature areas.  This is another key insight to why this parasite will completely/randomly infect your colony, as the shrimp are foraging creature that never stop probing for food.  The cycle of infection is endless unless you remove the visibly infected AND completely clean the substrate of ellobiopsid remnants. Here is my "subject 0" ellobiopsid specimen, a high quality bloody mary type neocaridina that cost me $8 each back in 2015. 

 

 My solution:  From my research and observations I concluded that the immune system of caridina and neocaridina differentiate enough to that the parasite only affects the latter.  So I thought to myself: let's assist the immune system by doing something it cannot- destroy the rooting system of the parasite.  I started to make medicated foods to treat this systemic parasite and I found that it actually worked in saving a few newly visibly infected neocaridina (pics below).  I used a variety of chemicals and I started with off-the-shelf brands, especially since there were other shrimp 'publications' that highlighted the use of ich medicated dips resulting in a cure.  I eventually crafted my own recipe through my experimentation with the intention of commercializing it for profit.  However, as I became busier with other ventures and also with the immediate lack of hobbyist importing infected shrimp (or admitting to having colonies affected with this incurable parasite) I've kept this information to myself until now, only donating my medicated food to those that have reached out to me on public forum.  This led me to realize that I needed to share this information with everyone, especially the Asian breeders to help eradicate this huge issue at the source, as it is definitely hurting the growth of our awesome hobby and community in the USA!  

Here is how you make your own medicated food to cure your shrimp and prevent it from occurring.  

  1. Locate a food that your shrimp will eat VERY quickly.  Pelleted snowflake (blended or powderized soybean hull) food is my recommendation since is it readily available by many vendors and also because it is extremely dehydrated so it will easily accept/adsorb liquid medication.
  2. Acquire a bottle of Kordon Rid Ich Plus for protozoans
  3. Place several pieces of your pelleted food onto a small dish and drip the liquid onto the food until it expands and can not accept/expand anymore. 2 mL of Rid Ich Plus per 1 gram pelleted snowflake (or pelleted barley, etc.) is a good place to start. You will notice that you may need to add more chemical to individual pieces to break it up further, add more Rid Ich Plus drop-wise until the food softens up.  The food does not have to be completely/overly saturated and untreated areas appearing are okay!  Each brand of pellet is a bit different, but I have tested this hydration method thoroughly and you will not reach toxicity levels.  It is normal for this process to take an hour or so for the pellet to absorb the chemical and fall apart, like I said before each brand has varying densities so the absorption duration will vary.   
  4. Let the (now powdery) snowflake food dry completely to lock in the medication

It should look something like this (note: however I used pelleted barley as I was experimenting with my own food brand at the time, but the food's just a delivery vessel in the end)

 

Now to cure you colony, you must first remove and quarantine every shrimp that shows signs of the ellobiopsid protozoan fruiting body (i.e the misnomer: "the green fungus").  If the shrimp is heavily infected I would recommend quick euthanization because they will not be curable by any means.  Lesser visibly infected do have a chance of being cured by feeding only the food for a week or longer.   Below are a series of pictures taken at two points of time showing the progress of two shrimp, one had lost most of its color but has accepted the medication and the ellobiopsid protozoan fruiting body is visibly compromised.  In the final picture, I had added another infected shrimp that I found in my colony for treatment (last picture on the left), but you can see the two other shrimp are on a course to improvement.

 

  After quarantining the contagious, I removed all of the healthy appearing shrimp from their old habitat (remember I medicated this colony for over a week) into a new, cycled aquarium. I netted them into a bucket of fresh RO water remineralized to match their old parameters.  Before I started netting I dosed the holding bucket with a standard dose of Seachem Paraguard while I gathered the entire colony.  The medicated dip was for reassurance that trace amounts of healthy ellobiopsidae protozoa would not transfer.  I waited several hours before transferring all of the shrimp into their new habitat, which they now share with my small collection of Black King Kong caridina.  I have been ellobiopsidae free for almost a year now!  Here is my colony today :)

 

About the author:  
Chaz Hing is the founder of ElevateShrimp.com, he has a bachelors degree in chemistry from University of Delaware and has lead entomology research at the USDA research service in Newark, DE.  He has a passion for aquariums and water chemistry and strives to grow the freshwater shrimp community by sharing his knowledge, research and innovation.