My youngest has a small fish tank that has a very strong current. We tried tanks without aeration and filtration, but they really do give the poor fish a short lifespan. We put guppies in the tank, which do well, and are pretty, but struggle against the flow of the filter especially when they are small or have any difficulty swimming. When we lost the last guppy (there is also a snail, which does really well in the tank), I decided to see what I could do to break up the current. I cut off the top of the pineapple house with a band saw, sanded the edges smooth, and took two plastic mesh tubes (from buying wine bottles, those net sleeves? Very useful to keep around), and set those up around the intake for the filter. I used two nets and offset them to reduce the chance of a fish slipping through.

We then put guppies in the tank and it seems to be working. The fish have a larger area to swim, and don’t seem to struggle constantly with the flow (although the output from the filter’s waterfall does still impact their rhythm when they go through, but it doesn’t seem distressing). The filter pump is still working well and water flows through the system. Now we see how the little pond does long term.