Who Gives A Fish Forums

Just set up a 75-gallon tank for my Discus, but I'm worried the LED lights might be too intense. They're on for 8 hours a day, and the fish seem a bit skittish. Using a Finnex Planted+ 24/7, sand substrate, and a few pieces of driftwood. Water params are good, 0 ammonia, 0 nitrite, 5 nitrate, pH 6.8. Temp's at 84°F with an Eheim heater. Anyone else run into this?

Bright lights can definitely stress them out, especially if they're new to the tank. I've got a similar setup, 90 gallons with Fluval Plant 3.0, but I dim it to 50% for the first month. Try reducing the intensity or adding floating plants like frogbit to diffuse the light. How long have they been in there?

Thanks for the tip. They've only been in for about a week. I'll try dimming the lights and see if that helps. Appreciate it!

Magpie wrote: ↑Tue Jun 24, 2025 7:03 pm Bright lights can definitely stress them out, especially if they're new to the tank. I've got a similar setup, 90 gallons with Fluval Plant 3.0, but I dim it to 50% for the first month. Try reducing the intensity or adding floating plants like frogbit to diffuse the light. How long have they been in there?

Yep, floating plants are a game-changer. I use red root floaters in my 120-gallon, and the Discus chill way more under them. Also, check if the tank's near a window. Sunlight plus LEDs can be overkill.

My dude, I had the same issue with my cheap Amazon LEDs. Fish were freaking out until I slapped on some window tint film on the back glass. Now it's all good, and they're coloring up nice. Maybe try that if dimming doesn't cut it?

I'd second the floating plants idea. My Discus tank has a mix of frogbit and dwarf water lettuce, and the fish seem way more relaxed. Also, how's your water flow? High flow + bright lights can make them bolt. I run a canister filter with the spray bar pointed at the back wall to keep it gentle.

Mine hated bright lights too. Switched to a dimmer schedule, 6 hours at 30% intensity, and they're way happier. Tank's a 55-gallon with black sand, lots of driftwood, and Anubias. No plants floating yet, but might try that next. What's your feeding routine like? Mine get frozen bloodworms twice a day.

Not sure about the lights, but my Discus tank has a dimmer switch. Maybe your LED controller has one? Mine's a Nicrew, and it was cheap. Tank's 65 gallons, temp at 82°F, with a sponge filter and some Java fern. Fish seem fine with the light at 40%.

If the fish are hiding or darting, it's probably too bright. My 75-gallon has a Twinstar LED, but I keep it low for the first few weeks. Also, check the color spectrum. Cool white can be harsher than warm. I switched to a 6500K bulb, and the fish calmed down.

Bijack wrote: ↑Tue Jun 24, 2025 10:45 pm I'd second the floating plants idea. My Discus tank has a mix of frogbit and dwarf water lettuce, and the fish seem way more relaxed. Also, how's your water flow? High flow + bright lights can make them bolt. I run a canister filter with the spray bar pointed at the back wall to keep it gentle.

Exactly! Flow matters too. I've got an FX6 with the output baffled by a sponge. Discus hate strong currents, especially when they're stressed. What's your tank's background color? Darker backs can help reduce glare.