Save some sand and save some fry

So you have a community tank. In that tank, you have a breeding pair of some species and they are spawning. You’re inclined to let nature take its course with regard to any offspring.  Therefore you don’t segregate the eggs, the wrigglers, or the fry.

That is my approach too (unless I’m taking fry to my LFS, which is a post for another day). However, I am careful to avoid vacuuming up any offspring. Most of the time, my approach works. When it doesn’t and I do vacuum up fry, I don’t lose them. How?

Though I use a Python hose, I don’t use it the conventional way. In fact, I use it in reverse. Let me explain. Because I have sand substrates, I don’t like sucking up lots of sand. I also have lots of rockwork, so I can’t get the Python suction tube into the nooks and crannies. Also, all the water that gets removed from my tanks goes into a three gallon bucket. The bucket sits inside a plastic storage bin.

So what do I use to vacuum the substrate? See my post about Pex pipe vacuuming. The drain end of the Pex pipe hose is threaded through a hole in the top of a three gallon bucket, which has several additional holes drilled in the top. As water fills up the bucket, it flows through the open holes. It then runs down the side of the bucket and into the plastic storage bin. The holes aren’t necessary since the water could flow over the top of the bucket, but I like to keep the water line below the edge in case I need to lift the bucket out quickly.

Because the drain end of the Pex hose extends down toward the bottom of the bucket, any fry that get accidentally sucked up end up in the bucket. Because fry instinctually stay near the bottom, I don’t have to worry about them going into the plastic bin.

So how do I get water out of the plastic bin when it fills up? This is where the Python comes in. The faucet attachment end is connected to a submersible pump that sits in the bottom of the plastic bin. The vacuum tube of the Python goes into a utility sink in my fish workroom. Sound complicated? It’s not.

See the photos below for what the set-up looks like.

My water change set-up. Note the drain end of the Pex hose (yellow arrow) is low in the bucket and the suction end with the Pex attached (red arrow). Photo by the author.


Three gallon bucket for catching fry. Note the extra holes at top (yellow arrows) to allow water to flow into plastic storage bin. Photo by the author.

Doing water changes this way, I accomplish three objectives:

  1. I lose less sand than I would using the conventional Python vacuum tube in the tank,
  2. using the Pex hose set-up I can get into tight crevices to remove detritus, and
  3. any fry that get sucked up don’t go to the utility sink and subsequently down the drain.

When I finish cleaning the tanks, I remove the three gallon bucket from the plastic tub, place it on a counter with good overhead light, and look for any fry. If I find any, I simply remove them and return them to the tank.


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