discus fry tank water testing
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mistysea - Posts: 8
- Joined: Mon Sep 26, 2022 4:15 pm
discus fry tank water testing
My Discus fry tank's water params are all over the place. Ammonia's at 0.25 ppm, nitrites 0.5 ppm, nitrates 20 ppm. Tank's a 20-gallon with sponge filter, temp at 86°F. I do 30% water changes daily, feed them crushed flakes and baby brine shrimp twice a day. They're about 3 weeks old. What's the best way to stabilize this?
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picker - Posts: 15
- Joined: Sat Feb 17, 2024 9:28 am
Re: discus fry tank water testing
Those nitrites are sketchy. You gotta get them to zero ASAP. Double up on water changes, maybe 50% daily for a week. Use Seachem Prime to detoxify the ammonia and nitrites. Also, check your sponge filter's flow rate. If it's too weak, it won't handle the bio load. What's your pH? Discus fry need it stable around 6.5–7.0.
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mistysea - Posts: 8
- Joined: Mon Sep 26, 2022 4:15 pm
Re: discus fry tank water testing
Thanks, pH is 7.2. I'll bump the water changes and grab some Prime. The sponge filter's an AquaClear, rated for 20 gallons. Should I add another?picker wrote: ↑Tue Jul 22, 2025 3:57 pm Those nitrites are sketchy. You gotta get them to zero ASAP. Double up on water changes, maybe 50% daily for a week. Use Seachem Prime to detoxify the ammonia and nitrites. Also, check your sponge filter's flow rate. If it's too weak, it won't handle the bio load. What's your pH? Discus fry need it stable around 6.5–7.0.
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masterd - Posts: 18
- Joined: Sun May 05, 2024 1:49 am
Re: discus fry tank water testing
Yep, another sponge filter wouldn't hurt. I ran two in my 20-gallon fry tank last year, and it cut the nitrite spikes big time. Also, try feeding less. Twice a day's cool, but maybe smaller portions. Overfeeding's a sneaky culprit for messed-up water. How many fry you got in there?
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kadyash - Posts: 20
- Joined: Mon Jan 17, 2022 9:00 am
Re: discus fry tank water testing
Honestly, 20 gallons for fry is pushing it unless you're running a bare-bottom tank with no decor. You're fighting an uphill battle with that bio load. I'd move half to another tank if you can. And yeah, Prime's a lifesaver, but it's a band-aid. Fix the root cause or you'll be chasing params forever.
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Hued - Posts: 20
- Joined: Thu Aug 03, 2023 8:36 am
Re: discus fry tank water testing
For real, though. I've been there. Split 'em up if you can, and ditch the substrate for now. Bare-bottom's way easier to keep clean. Also, what's your water change routine like? You using aged water or straight tap?kadyash wrote: ↑Tue Jul 22, 2025 8:11 pm Honestly, 20 gallons for fry is pushing it unless you're running a bare-bottom tank with no decor. You're fighting an uphill battle with that bio load. I'd move half to another tank if you can. And yeah, Prime's a lifesaver, but it's a band-aid. Fix the root cause or you'll be chasing params forever.
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picker - Posts: 15
- Joined: Sat Feb 17, 2024 9:28 am
Re: discus fry tank water testing
Aged water's key. Straight tap can mess with the pH and stress the fry. Let it sit for 24 hours with an airstone. And yeah, bare-bottom's the way to go. Easier to siphon out leftovers. How often are you cleaning the sponge filter? It might need a rinse in tank water every few days to keep flow up.
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mistysea - Posts: 8
- Joined: Mon Sep 26, 2022 4:15 pm
Re: discus fry tank water testing
I'm using tap with Prime, but I'll start aging it. Tank's bare-bottom already, and I've got about 30 fry. Sponge filter gets rinsed weekly in tank water. I'll add another filter and cut feeding portions. Thanks, everyone.
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masterd - Posts: 18
- Joined: Sun May 05, 2024 1:49 am
Re: discus fry tank water testing
30 fry in 20 gallons is tight. You're gonna need to upgrade or cull soon. They'll outgrow it fast. Keep us posted on the water params after the changes.
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kadyash - Posts: 20
- Joined: Mon Jan 17, 2022 9:00 am
Re: discus fry tank water testing
Yeah, 30's a lot. You might wanna think about selling or giving some away once they're bigger. Otherwise, you'll be doing water changes every other hour. Good luck!