Snail-Proof Intake Guard for Rear-Filter Aquariums

A box-shaped grille that is siliconed over the corner opening into a rear filter chamber. If a snail parks on one face, the other faces keep passing water.

Rear-filter and all-in-one tanks draw water through an opening in the divider glass. A flat grille over that opening is easy for one adult apple snail to block. This guard is a box instead: three grille faces (front, side and bottom) stand out 40 mm from the glass, so a snail on one face leaves the others open. Slots are 2–2.5 mm wide, under the 3 mm at which juvenile apple snails start to get through.

What it fits

• Corner openings up to 42 × 30 mm in the divider glass (the guard covers the opening; it does not plug into it).

• Two files: opening at the top-left or top-right corner of the divider, seen from the tank side.

• The top face is open (it sits at the water line) and the side face next to the side glass is open.

What you need

• PETG filament (do not use PLA under water).

• Aquarium-safe silicone.

Print settings

• Material: PETG

• Nozzle: 0.4 mm (ours was printed with a 0.6 mm nozzle)

• Layer height: 0.18–0.2 mm

• Walls: 3–4

• Infill: any (walls fill most of it)

• Supports: None. Do not turn supports on: they end up inside the grille.

• Orientation: Open back face down on the plate (as in the file).

• Bed: Fits A1 mini / 180 mm beds. 54 × 42 × 43 mm.

• The front grille bridges about 35 mm across thin air; it printed clean on our P2S.

• Clean the plate with IPA first.

Files

• intake-guard_top-left_42x30.stl — opening at the top-left corner

• intake-guard_top-right_42x30.stl — opening at the top-right corner (mirror image)

Fitting

• Dry-fit first: hold the guard over the opening; the two fixing tabs should sit flat on the glass.

• Silicone on the back of the tabs, press over the opening from the tank side.

• Leave the silicone to cure for 24 hours before the water goes back.

Limits

• Fixed size: openings larger than 42 × 30 mm are not covered.

• Silicone holds it; snails hang on it, so let the silicone cure fully.

How it was checked

Printed and in use: we printed this design (the top-left file) and it is siliconed into our own tank, which keeps apple snails and fish. The top-right file is its exact mirror image.

Safety

• Use PETG and aquarium-safe silicone only, and let the silicone cure before the water and animals go back.

A parametric version of this part is on mislastudio.com: https://mislastudio.com/m/grelha_filtro?utm_source=printables&utm_medium=free_model&utm_campaign=grelha-filtro

Designed by Misla, a small studio of engineered 3D-printable parts: https://mislastudio.com/?utm_source=printables&utm_medium=free_model&utm_campaign=grelha-filtro