Who Gives A Fish Forums

Just set up a 20-gallon tank for my Discus fry, but the water flow seems too strong. They're getting pushed around by the filter output. Using a HOB filter with adjustable flow, but even on low it's sketchy. Anyone got tips for calming it down without losing filtration?

Yep, HOB filters can be rough on tiny fry. Try adding a sponge pre-filter to the intake and a baffle on the output. I cut a plastic bottle to diffuse mine, works like a charm. What's your water change routine? Frequent changes help keep things stable for them.

Lexi wrote: ↑Sat Jul 19, 2025 7:22 pm Yep, HOB filters can be rough on tiny fry. Try adding a sponge pre-filter to the intake and a baffle on the output. I cut a plastic bottle to diffuse mine, works like a charm. What's your water change routine? Frequent changes help keep things stable for them.

Solid advice. Also, consider a sponge filter if you're gonna stick with this tank long-term. They're gentler and provide bio filtration. What's your temp at? Fry need it steady around 84–86°F to thrive.

My fry tank's got a sponge filter and a tiny powerhead for flow. They seem chill with it. How old are your fry? If they're super young, even a gentle flow might mess with them.

Thanks for the ideas. They're about 2 weeks old, and I'm doing 25% water changes daily. Temp's at 85°F. Gonna try the bottle baffle tonight. The sponge filter's a good call—I'll grab one this weekend.

Daily changes are perfect. Just watch the baffle doesn't trap debris. What's your substrate? Bare bottom's easier for fry tanks, but if you've got sand, keep it thin to avoid dead spots.

Bare bottom's the way to go for fry. Easier to clean, and you can see all the gunk. What're you feeding them? Baby brine shrimp and crushed flakes should keep 'em growing fast.

novaby wrote: ↑Sun Jul 20, 2025 12:16 am Bare bottom's the way to go for fry. Easier to clean, and you can see all the gunk. What're you feeding them? Baby brine shrimp and crushed flakes should keep 'em growing fast.

Yep, and don't forget to siphon the bottom after feedings. Leftover food's a nitrate factory. How's the lighting? Too bright can stress 'em out.

Good point on the lighting. I run mine low, just enough to see 'em. You got any plants in there? Floating ones like frogbit can help diffuse light and give 'em cover.

Bare bottom with a few java ferns tied to driftwood. Lighting's on a dimmer, so I'll keep it low. Feeding baby brine and powdered fry food. The baffle worked—they're not getting tossed around anymore.