| | Planaria and Hydra Elimination in Shrimp Tanks
I have been keeping dwarf shrimp for about 5 years beginning in late 2003. At first I only had Amano and Cherry Shrimp since they were the most commonly available species at the time. In December of 2006, I set up a shrimp rack that would hold twelve 10 gallon tanks for breeding shrimp. In addition to the Amanos and Cherries I collected several varieties of shrimp including, Crystal Reds, Yellows, Blue Pearls, New Bees, Blues, Snowballs and Dark Greens. For some reason, I was not getting many baby shrimp even though most tanks had at least one berried female in them at all times. All of my tanks had planaria in them and I had been assured by some local hobbyists that planaria were harmless to shrimp. I have since found this article: TheTrouble with Planaria, and have come to the conclusion that the planaria were indeed detrimental to my shrimp population.
Then, on the 4th of February, 2008, I noticed a young Snowball Shrimp falling lifeless to the substrate. A berried female was on the thermometer and she appeared to be releasing new born shrimp. After a close inspection of the thermometer, there were several Hydra on it. Upon seeing this, I came to the conclusion the Hydra had killed the newborn Snowball Shrimp. This is purely speculation since I did not see the Hydra actually kill the shrimp. Not only do I have planaria in my tanks that can harm my shrimp, but I also have hydra whom seem to be responsible for at least one shrimp death.
Though I prefer not to medicate my tanks, I decided to take action and look for a cure to my problem. I have seen flubendazole mentioned as a medication against planaria, but it is very difficult to find here in the United States. I decided to try using fenbendazole (a medication used to de-worm household pets and livestock) after searching for flubendazole unsuccessfully and attempting manual removal of the planaria and hydra over the course of several months.
Fenbendazole is most easily found as a dog de-wormer and can be purchased at most pet supply stores. I used the “Safe Guard” brand labeled for dogs. Panacur is another brand name product that can be used. The price was about $14 for four 1 gram packs. This was the smallest size available at my local fish shop. Online information is “sketchy” at best for using this medication in aquariums. Some people describe using a "pinch" of the powder for their tanks or using a "BB" sized measuring spoon for their tanks. Most accounts do not give the volume of their tanks so figuring out a dosage from their information is next to impossible. The best information I could find suggested using a 2ppm dosage to de-worm fish. I was worried about the effects on shrimp with this dosage so I calculated a much smaller dosage for my shrimp tanks. According to the package, one gram of the powder contains 222mg of fenbendazole. Therefore, 0.1gm would contain 22.2mg and this would be about 0.6ppm (can someone please double check my math) dose for my 10 gallon tanks.
I added 0.1gm of fenbendazole to my 10 gallon Amano and Blue Shrimp tank on the 5th of February. This tank had both planaria and hydra present. On the morning of the 6th the planaria seemed to be gone but a few Hydra were still hanging on. On the evening of the 6th, I added another 0.1gm dose of fenbendazole and by the time the lights came on in the tank on the 7th, all the Hydra seemed to be shriveled up and dead. The shrimp, snails and two Rasbora espei in this tank were doing fine.
I decided to go ahead and dose my 10 gallon Cherry shrimp tank with the same dosage on February 6th. This tank had planaria but no apparent hydra and the dosage was effective on the planaria by the next morning. As with the Amano and Blue Shrimp tank, no effects on the shrimp were noticed.
On February 10th, I dosed the remainder of my shrimp tanks (8 additional 10 gallon tanks) with 0.1gm of fenbendazole each. I decided to wait 48 hours (instead of the 24 I waited on the Amano and Blue Shrimp tank) before adding the second dosage to see if a little more time will kill the hydra. The single 0.1 gram dose of fenbendazole worked for both the planaria and hydra in all of my tanks when I waited 48 hours versus 24 hours. A water change was not completed on any of the shrimp tanks after adding the fenbendazole due to it's insolubility. All tanks received their normally scheduled, weekly water change on the 13th of February.
I do not know if the fenbendazole has any effect on the beneficial bacteria at this point. Since I have such a low bio-load in my shrimp tanks, I did not test for ammonia or nitrites prior to adding the medication. If I have to re-medicate the tanks in the future, I will increase the bio-load prior to treating and check both the NH3 and NO2 levels before and after dosing.
Since shrimp can be very susceptible to most medications, shrimp only tanks can be can be very difficult to rid of pests. A 0.6 ppm dose of fenbendazole seems to be highly effective against both planaria and hydra in shrimp tanks and does not harm shrimp, snails, or other fauna, at this dosage. Four months have passed since first dosing fenbendazole in my shrimp tanks and the planaria and hydra are still absent from the tank. Every species of shrimp has bred successfully for me to this point, even the Amano Shrimp. However, I have been unsuccessful thus far in raising the Amano larvae. A smaller dose of fenbendazole may be effective against planaria and hydra but I have not experimented with it yet.
Note: Measuring 0.1 gm of fenbendazole is difficult for most hobbyists. Since it is very insoluble in water, I have suggested to fellow hobbyists that they simply divide one 1 gram packet into ten equal parts and add one of these parts for each 10 gallons of water. So far, everyone has had success using this method. If measuring a 0.1 gram dose is not possible, a water change after 48-72 hours would probably be a good idea.
Last edited by hooha; 01-19-2009 at 10:29 PM..