The snails are no problem they come with the territory of owning any type of aquatic plants. If they start to overtake get some loaches if you have the room or place a piece of wilted lettuce in the tank at night and remove the attached snails and lettuce the next morning. Repeat if necessary. Some "things" might be mosqitto larva. I cant remember what the other "pond dwelling things" are.I am sure someone will be able to properly I.D. them. The plants that come from a pond usually have alot of critters in them besides the snails. Make sure you use only plants ment for the tropical aquarium in your aquarium and pond/bog plants in the pond. Some people use bog and non aquatic plants in their tanks but usually end up with problems.

Your little "hopping dots" could be Daphnia or some other tiny freshwater crustaceaus water bug. None of these are parasitic that I know of, & small fish actually enjoy chasing them down & eating them. In fact, Daphnia used to be availabe in stores years ago as live food.

Your worms could be just that - freshwater aquatic worms - or they could be some type of midge larvae. Most of these are used as fish food as well.

I doubt anything in your pic is harmful or parasitic to fish, but I'm certainly not an expert.

argh, expired image hosting! here they are again:

tubfex/black worm:
{{gwi:377371}}

a segmented worm that swims well:
{{gwi:377373}}

cyclops:
{{gwi:377374}}

copepod

Could the worms be a type of planaria? As far as I understand, some types of planaria are not harmful to fish, they live off decaying plant matter and decaying food in the water. Their presence, however, usually means an aquarium needs a good gravel cleaning and water change. I know that part doesn't really apply here, as you likely got the critters on plants you bought or in aquarium water.

If they did hitch a ride with the plants you received that may mean they aren't harmful, if the aquarium that had the plants in it had no fish in it. They may have simply survived on decaying plant matter.

One source did say that salt in the water may kill them or else some fish may eat them. Not sure of the exact dosage, but I will leave that up to you to research.

I had a new aquarium that had plants in it, but no fish. I did fishless cycling. Right before I was ready to add the fish, I noticed these planaria. I reasoned that they had to be living off the decaying plants and such, because there had never been fish in that tank. Still, I added a bit of salt before adding the fish.

glen

They might in fact be black worms. I see in the top corner they're balling up. With breezy saying the others look like daphnia and jim guessing copepod...I'd guess the fish in the plant tank were taken care of with plenty of live food.

The "Mickey Mouse" creatures are Cyclops, a type of crustacean. The smaller ovals are egg sacs. They have been reputed to attack tiny "fry" but adult fish would probably like making a meal of them, as well as the worms you show. Unless you are trying to breed egglayers in the tank, don't worry.

Not sure what the worms are. cyclops is a common name for copepod.

They could be either white or black worms...but my bet would be black worms in the first pic ana white worm in the second (could be light diffs making them look differnt too). Planaria are shorter and look more like a white, tranlucent snail without a shell (they are actually flatworms) Both black and white worms are sold as food, so if they came with the plants...BONUS! Free food. Planaria are a sign that you are over feeding and there is is a lot of waste food and fish waste in your gravel. A good gravel cleaning and water change usually clears them up. Planaria are not harmful to fish. Some fish may also eat them.

Eric

yummmm
so they are pretty much food for my fishes!
I kept them in a tupperware till now, so now I will see about releasing the lot into my tank. as for the riccia, it might not be used because I don't like its fragileness, much like Najas sp.
thanks so much for your help!