There is also a grid on the very top as well to ensure no inhabitants are able to enter from the top side. Our skimmer features 4 suction channels with two partitions in the middle of each to prevent small fishes, shrimps, and snails entering the skimmer main chamber. The original skimmer on the Eheim 350 has huge gaps which causes small inhabitants to be sucked into the skimmer chamber. It now has increased buoyancy and better skimming capabilities. This is the new MKII model based on our older version. ( 2022 revamped edition ) Available with output diffuser add-on option. It impedes skimmer function only slightly more than number 3, but still allows for effective skimming.Custom designed 3D printed Skimmer for the Eheim Skim 350. Should keep out shrimp down to sub-adult size. The water goes through this mesh very easily and since the surface is larger it can take more than two plant leaves before clogging. The modification steals a little bit of movement room from the skimmer. It also happens to be my favorite material for use in securing pump outlets from athletic and suicidal fish. The mesh is stretchy and easy to wrap around things, but a bit delicate so take care when cleaning it and dont pull too hard. Modification number 5 is my favorite so far. That was not a risk I was willing to take. I have not tested this one for long as there is a chance fish will go over the top and end up in the skimmer. You could probably experiment with different densities of mesh to find one where the water will go mostly unimpeded through the holes while keeping critters out. This mesh is much too fine and the water just bypasses the mesh and flows over the top. It goes inside the slots like in the second picture here that I have shamelessly stolen from the internet. Modification number 4 is stainless steel mesh cannibalized from a shrimp intake guard. With this mesh the skimmer function is barely disturbed, but it needs to be kept an eye on, because a few plant leaves will clog it up and the skimmer will suck down the head and stop skimming. This will only keep out shrimp down to sub-adult size, but I found in my tank that the smallest baby shrimp tend to stay in the plants and not swim about that much so I found it to be an acceptable tradeoff. I cut the mesh to fit between the slots and attached it with synthetic sewing thread under the lip of the head to lock it down. If the ebay link expires some time in the future, it can be found by searching for 'Plastic drainage mesh'.

Modification number 3 is a stiff mesh made of plastic. The modified skimmer head will need to be cleaned often. This mesh should keep out all but the absolutely smallest baby shrimp, but you lose some effectiveness of the skimmer. It should be possible to get the material in black as well. I bought mine from a local store but found a very similar looking product on ebay. Modification number 2 was this mosquito netting made to cover your head. (Skimmer part +final modification for scale in photos). The mesh is completely baby shrimp proof but almost completely inhibited the functioning of the skimmer. Modification number 1 was a covering of this very fine mesh, repurposed from a bird cage seed catcher from ebay. I have tried out various materials and figured I would list them here for the benefit of others I recently purchased an Eheim Skim 350 and found myself in the same spot as many others, needing to shrimp and fish-proof the skimmer opening.

Protector skim 350