Dark discus

[Eric.tech]

Alright folks, going to poll the audience on this one. I have 8 discus, some rummy nose and cardinal tetras, a few plecos, and 2 rams. The display tank is a 75g and the sump is a 20G long. Total water volume is around 80g. As you can see in the photos, the discus are all very dark and a few white tufts on the fins. The female appears to have some fin rot going on, but I have not been able to nail down what it is. They are flashing and every so often breathing out like they are trying to spit something out. I’ve tried the following meds:

Kordan rid ich plus, treated about 3 weeks
Seachem paraguard, treated about 3 weeks
Currently running prazipro in case gill flukes, about one week.

Water change regiment is every 3 days.
Water parameters are as follows:
PH: 7.0
Nitrite: 0ppm
Ammonia: 0ppm
Nitrate: 0ppm

My filter consists of a wet/dry filter, matrix under the wet/dry, and 3 sponge filters. There’s also an algae scrubber running. I’ve taken a skin scrape and I can’t see any flukes, though I haven’t been able to take a fill sample. I’m thinking it’s possibly fungal/bacterial. The fish are not sluggish and are eating well. Obviously I’ve tried a few things, but nothing seems to be helping. Thinking with the signs of fin rot on my female, maybe try some Kanoplex? Also, when the female was laying eggs, a few had fungus on them. Any input would be greatly appreciated as I’m trying to avoid using PP.

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Photos of the skin scrape:
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[Eric.tech]

Also forgot to add that the water source is from a 7 stage RO system

[Iminit]

I think you need to up your water changes. Every day 50% or more. First pic the left side discus is showing pimples as is the orange discus. The second pic the fish looks like it’s not eating. What’s your temp and why the ro water? Is your tap that bad? The reason for more water changes is they look like large discus. You’ve got 8 in a 75. So you need more changes. The pimples are a sure sign of bad water quality. Plus all the meds you’ve added haven’t helped the water quality. Change the water daily for 2 weeks and you will see changes. Good luck.

[Eric.tech]

My current temp is 86 degrees F. The tap water here is not the best, over 400tds and over 13dkh, extremely hard. I have a reef tank and pass the RO through additional DI stages for that tank, but only RO wo/DI for the discus tank. It’s agreed that it appears that in the second photo she’s not eating, but she is eating, quite enthusiastically. Another reason why I was trying prazipro incase of a tapeworm issue. I’ll up the water changes and monitor.

Do you think the bacterial load in the tank is high and causing an issue as the other parameters are low? Also, should I stop the prazipro and install the UV I have waiting to go into the system? It’s a 15 watt aqua uv unit. Appreciate the input!

[Iminit]

The lean fish may need to be moved to a qt . Raise the temp and add salt and see how it goes. The temp is right so it maybe hormones in the tank. Water changes will help. I don’t medicate. Most I’ve used is salt.

[bluelagoon]

How often do you clean the substrate? How much %WC each time? You must have a typo on nitrates; should not be a zero. Agreed more frequent large WC's are needed, especially when tanks are over stocked. Second pic looks like he's too far gone to fully recover, grow well and live a long life.

[jeep]

Your water is similar to mine and it's fine, although I would re-test your parameters. 0 nitrates are not possible in a cycled filter bed. It's very hard to treat fish in a planted tank, which is why we recommend bare bottom for grow outs, and at least a hospital tank for emergencies.

You're tank is pretty maxed out on population and I'm convinced this is a water quality issue that can be corrected by deep cleaning, increased water changed and either reducing the population or getting a larger tank. The Turq's are very thin and are wasting away. There's more to water quality than nitrates and water changes alone. Have a look at this thread http://forum.simplydiscus.com/showth...-Are-Important

[AquaticNerd]

All the advice here is solid. My only comment to the group would be that 0 nitrates could be possible, depending on how effective the plants & algae scrubber are at removing excess nitrate. When I had a heavily planted tank ages ago it consistently tested at 0 nitrate. With that said, I definitely agree with Brian here that there's more to water quality than just good parameters and always did frequent water changes no matter what. Back then, I didn't have discus in that aquarium because the more frequent WCs made it counter productive to dosing fertilizers.

[Eric.tech]

Thanks all for the advice. I agree the tank is packed to capacity. The test kit I’m using is the API test kits, which I don’t trust that much, but coming from reef keeping, not sure what other options are out there for freshwater testing. The algae scrubber is very effective on reef tanks and seems to be working well on the fresh water tank, but I will be changing the water daily as recommended here. I’ve been doing 50% water changes with RO water heater up to 86 degrees.

Should I up the amount that I’m changing out? Also, when things do settle down and the fish heal up, do you think I should then back off to every other day, and then keep a 3day water change regime due to the stocking level?

[Eric.tech]

Forgot to add, I clean the substrate weekly. There’s only about 1/4” to 1/2” of substrate in the tank. I have a couple of 20 longs and a 10 gallon that can be used for hospitals/qt.

[Iminit]

Yes once things settle down you can reduce water changes. Those pimples will appear when your over doing it. My main 125 is on a 3 day a week schedule. 150g a week. And has been doing good. I clean one side of the gravel at each water change. For now I would recommend a 125 or bigger tank for your fish. Plenty of good deals online for used.

[Eric.tech]

I have a 30 gallon that will hopefully be cycled here soon as there is a breeding pair in the tank that we’re laying eggs regularly and hatching. The fry would last a few days and then the would be consumed. Was hoping to use the 30 for a breeding tank and that would also lessen the load on the 75 for now. I agree, a 125 would be wonderful for them. What’s a good rule of thumb for discus, how many fish per 10gal? Again I’m coming from the Salt water reef side of things. I tell my reef keeping buddies that discus are harder to maintain than a reef tank 😂 granted, I don’t keep small polyp Stoney corals.

[Eric.tech]

A big thanks for all the input guys!

[AquaticNerd]

General rule of thumb is one discus per 10 gallons if in a species only tank. Given that they're social fish, many recommend not keeping fewer than 5 in a 55. I personally feel like a 55 is a little too small, considering the 13" depth, but many are successful using that size. A 75 like you have is a great starting place dimensions wise, but like others have pointed out your setup is currently quite high on the stocking capacity.