I have surprise fry in one of my tanks (I've counted 8 or 9 so far).

I've removed all the adults into a separate tank, so the fry won't be eaten.

I have apple snails in the tank as well. These guys create a lot of waste.

I've removed the filters so that the fry don't get sucked into it. I can't use a sponge filter because the snails eat it. Now I have waste accumulating on the substrate. I don't want to vacuum it, because I don't want to suck the fry out.

I can't remove the fry from the tank to clean, because they're difficult to see and I could not be sure that I got them all.

What other methods are there that I can use to remove the waste?

  • The answer you are looking for is a water syphon as described in this answr Hopefully someone will post a fuller answer and link to Rebecca's post as well Commented Jul 10, 2018 at 14:44
  • Also the answer at this question How do I do a water change in my fish tank? while is hints at the answer you need, it is not specific to fry so I don't think it is a duplicate. Commented Jul 10, 2018 at 14:55
  • What kind of fish? For small fry , there is likely creatures living in the waste that the fry can eat. Commented Jul 11, 2018 at 16:18
  • I have many giant danio fry of all sizes in my pond . Their primary food is whatever they find in the inch of stuff on the bottom. This works very well. Commented Jul 11, 2018 at 16:22
  • @blacksmith37 Surprise fry :) I'm not sure of their species. They could be danio, loach or gourami. Currently, they're about 5mm long. The problem isn't about feeding them. It's about getting the snail and other waste out of the water without losing fry.
    – Richard C
    Commented Jul 11, 2018 at 16:33

1 Answer 1


In my experience with guppy fry, I didn't have any issues vacuuming around them (in a 20 gal planted tank). I just have a simple siphon vacuum and got it running out of the tank, then "paused it" by plugging the outlet tube with my finger, then positioned it in the tank low to the ground and let it flow again. They fry stayed away from my hand and the tube and I just kept it low and had no issues!

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