Enemies

For a couple of months now, I have seen some planarians in my main aquarium. At first I attempted to combat them using traps to remove them; small plastic containers that the small worms can crawl into but struggle crawling out of. It worked alright for a while - put a bit of food in the trap and stick it in the aquarium overnight. In the morning, euthanize the captured planarians with a quick dose of boiling water, rinse and repeat.

Sadly, that didn’t really do much, and the population of these flatworms remained relatively stable no matter what I did. But, they didn’t seem to affect my shrimp much at all - at this point I have somewhere near 50 shrimp of various sizes. But the population wasn’t growing much more than that. I was first thinking that that might be the plateau that they’ve reached, what the ecosystem in my tank could sustain.

But then, the other day, as I was walking past the aquarium I saw one of my poor baby shrimp jolting around in the water. As I investigated, I saw that this shrimplet had a planaria stuck to it, which was causing it to jolt around.

I had tolerated them up until that point, but seeing one of my shrimp be antagonized like that, and I knew that no flatworm could be left alive.

First step - evacuate my snails from the aquarium. I was going to have to fight the worms with chemical means - the only means of truly eradicating them from the aquarium. And most wormicides also harm snails, while they leave shrimp mostly unaffected. So my
Clithon Corona were moved to my smaller tank.

Now, I know that snails are highly susceptible to parasites, and the chances of a planarian hitching a ride on a snail to my smaller tank was much greater than zero. But, at the moment that tank only houses two Amano shrimp, who I am fairly certain are both male. The female I had hasn’t been seen for over a month, so I assume that she passed away either of old age, or stress related to molting. The two remaining shrimp probably had ample time to eat the body before I could spot it.

So with no possibilities of newborns in the smaller tank, the planarians can infest it if they like. When I do acquire the shrimp I plan to house in that aquarium, I will have dealt with any eventual infestation there as well.

So, once the snails were hanging out with the Amano shrimp, I went for a bike ride. It was raining, but I didn’t care. The solution to my problem was sold at the drug store. Once I got back, I immediately got to work.

I had acquired a dewormer for cats and dogs, Axilur brand, but any brand works as long as the active ingredient is fenbendazole. The package I bought had 10 pills with 250 mg of the active ingredient. And from my research the dose I would need would be 2.2 mg per litre of aquarium water. My aquarium is about 45L, and with some quick napkin math we can work out that half a pill is just slightly over the recommended dose. I could have measured it out more accurately mixing the ground up pill with a known amount of water, and then measure out a precise amount of water, and I was prepared to do so…

But then I would have leftover pill-mix, so I decided to just take half a pill, grind it up, and dump it in. Going to leave it in the aquarium for a couple of days before I do a water change and then dose with the other half of the pill, to kill any newly hatched planaria.