Night attack mystery

[Menagerie]

Hello everyone, I'm new to simply discus, well sort of, I've been haunting this site for a while gleaning good information but I come to you today with a question that I have yet to find the answer to.

First off I'm not new to fish I have a Nano reef a 75 salt tank, a Koi pond, flood tank, etc etc but the one fish I had not had was discus. So when I set up my 100 gallon fresh discus were going to be the star of the tank. So now to the parameters.

Stock 100 gallon tank
Planted but not heavily
Filtered with 2 aquaclear filters for 100 gallons with stock media
Also 2 uv sterilizers
Nitrite 0
Ammonia 0
Nitrate at or below 5 ppm (depending on water changes)
Temperature 84 degrees
Ph 7.6 (I know it's high for discus but that's what the tap has and the driftwood hasn't buffered it a lot yet)
The tank has been set up for a little over 3 months
I do water changes of 25 percent on Wednesdays and 50 percent on Saturdays or Sundays.

Stock list:
Serpae tetras
Orange tetras
Glass cats
Corydoris
Farowella catfish
Banjo catfish
Hatchet fish
feather fin synodontis
Ocellated synodontis
2 clown loaches
And 5, 3 or 4 inch discus
I added all the fish slowly by species over the weeks with the discus being the last added.

the fish are healthy and happy all day no extreme aggression to be noticed just typical feeding heiarchy. They are fed 3 times a day alternating between blood worms, mysis shrimp, emerald entrée, beef heart, shrimp pellets, and new life spectrum pellets.

Heres the problem. Everyone is happy during the day but when I turn off the lights to go to bed I am garunteed to wake up to a beat up discus the next morning. I use a blue moonlight led at night too so they're not in pitch black. My first suspect was the synodontids but the damage is picked fins and only on the discus not on any other fish. Generally if synodontis are aggressive it's to other bottom feeders and the wounds are slash marks from their barbs not picked fins. So is it possible that the discus are doing this to each other in the night? I was under the impression that they "slept". Please help because I am stumped. Thank you in advance :)

[musicmarn1]

can you put a video camera on the tank at night?

[Menagerie]

I don't have a camera other than my phone and with it being a 100 gallon the fish would be tiny specks. Is this typical for discus to be active at night?

[wild4discus]

The tetras you have can be fin nippers, especially the serpaes. Farowellas are also known to attach to discus on occasion, but normally don't cause fin damage.

[Menagerie]

It's the same 2 discus that keep getting beat up which makes me think the discus are doing it.

[musicmarn1]

i would suspect the discus but ive never kept clown loaches and everything i read here says thats a really bad match; clown loaches and discus usually = badness

i never kept them i might be wrong but i can think of about 12 threads where the OP pulled out the loaches !

[John_Nicholson]

It's the same 2 discus that keep getting beat up which makes me think the discus are doing it.

Its not the discus. Once the lights are out the discus will go to sleep. You have several type of other fish that might be doing it.

-john

[Rudustin]

It seems to me that you have a lot of nocturnal fish including the loaches. With so much activity at night Discus are apt to panic and be stressed out. Discus are day movers and keep relatively quiet at night. The various catfish that you have are principally active at night. I had loaches and found them to be very aggressive with discus. I removed mine. Hope this helps.

[OC Discus]

Probably not a good idea to keep nocturnal fish, or nippers like serapes with your discus. While they can't attack and kill the discus, the stress of being harassed at night and nipped in the daytime can cause the discus to become stressed and more susceptible to disease.

I have a couple of runts that always have slightly ragged tails because the other discus chase and nip. This is visible in the daytime. Never seen it happen much at night.

[Menagerie]

Thank y'all for all the good responses. I have moved the nipped discus into a breeder box as not to stress them to much by a move to a new tank needing an acclimation period while already under a lot of stress. I am also going to leave the lights on until they heal fully. I am also going to do some "night time" observations where I will turn out the lights the second it gets dark outside and in the tank so I can observe the activities of the fish at night and try to pinpoint the culprit. I am not against removing any other species as the tank is supposed to be for discus. I just don't wish to remove falsely charged fish. I noticed the serpaes are spawning so perhaps that has caused this recent night time aggression spike. But are serapes nocturnal? Also I have never once noticed the serpaes touch a discus, and I watch the tank a lot, like an unhealthy amount of a lot.

Its pretty safe to say its not the orange neons, hatchets, or the glass cats, right? I'm systematically trying to rule out species.

[Rudustin]

Thank y'all for all the good responses. I have moved the nipped discus into a breeder box as not to stress them to much by a move to a new tank needing an acclimation period while already under a lot of stress. I am also going to leave the lights on until they heal fully. I am also going to do some "night time" observations where I will turn out the lights the second it gets dark outside and in the tank so I can observe the activities of the fish at night and try to pinpoint the culprit. I am not against removing any other species as the tank is supposed to be for discus. I just don't wish to remove falsely charged fish. I noticed the serpaes are spawning so perhaps that has caused this recent night time aggression spike. But are serapes nocturnal? Also I have never once noticed the serpaes touch a discus, and I watch the tank a lot, like an unhealthy amount of a lot.

Its pretty safe to say its not the orange neons, hatchets, or the glass cats, right? I'm systematically trying to rule out species.
I don't think it's the neons or the hatchets or the glass cats. It may be simply that there is too much activity at night for the discus in general. I have seven tanks of discus. The only other kind of fish are a bristle nose catfish, and a strain of cory like catfish. I had some angel fish in with some of my discus and they were too aggressive for my discus especially when they were spawning so I removed them.

[Menagerie]

I thought dither fish were good for discus? Thats why I got the tetras in the first place.

[Rudustin]

Yes, they do well with dither fish. I'm not saying that they are the problem. I'm only suggesting that the nocturnal loaches, assorted catfish may be just bit overactive for your discus but of course I am only guessing. Just observe the tank when lights are out for a while and perhaps you will see what the problem might be. Discus are very sensitive to many things. So, a guess is all we have to the nipped fins. If your water quality is okay and the discus don't seem to be overly fighting then the cause has to be some other denizen in the tank. Wish I could be more helpful. Rufus

[Menagerie]

Mystery solved. I have been up fretting about this all night so I decided to take the chance and go ahead and turn out the lights to see if I could observe anything...the synodontids left their lairs and began rooting through the sand, the glass cats left the plants and began filtering the water, the tetras and hatchets tightened their schools and calmed down and the discus played a rousing game of PULL EACH OTHERS FINS OFF! The dominant discus went ham on his "daytime friends" pulling fins, chasing, the whole thing, which explains why the lower pecking order was getting beat up. And it took them no time to go at it either 5 minutes after the lights went off tops.

So why is this happening? If they're supposed to calm down when the lights go out why are they up at night fighting?

Could it be the moonlight? Come to think of it I didn't have this kind of aggression when it was pitch black. But plenty of people use moonlights and don't get "werediscus"

Also I have noticed the discus tend to pick on their own colors. I have 3 "wild types" 1 turquoise snake skin and one snakeskin pigeon blood. No one ever seems to mess with pigeon blood but the wild types are the ones always getting battle scars. Is this normal?

Discus are so weird. They are unlike any fish I have ever had and I have some weird fish. Does anyone have some great advice on this?

[Second Hand Pat]

Turn off the moonlights

[musicmarn1]

see the only reason i said i suspect it was the discus (though you have some fish i have never worked with , i have tetras with discus in my adult tanks and there has never been an issue )

was because ive had this happen myself and it was always when i woke up the damage was done, but i only had bullying early on, i have not had any real bullying since. For me the first time it was a pair forming and the second time my water changes were too low, i had cranky discus im guessing!

hehe well mystery solved, hopefully *lights out* should calm things down for you!

[Rudustin]

I agree with Pat. Try shutting off all the light at night. Glad you found out who or what it was.

[bluelagoon]

But you still have fish in the tank that shouldn't be with discus so you will still have issues.I can see the Farowella going for the slim and leaving marks on your discus;been there,done that!Those tetras are not the best choice;they are fin nippers.Anything that comes out at night and feds;may as well take them out too.After all they are only a few inches yet.

[Miss_Fish]

Mystery solved. I have been up fretting about this all night so I decided to take the chance and go ahead and turn out the lights to see if I could observe anything...the synodontids left their lairs and began rooting through the sand, the glass cats left the plants and began filtering the water, the tetras and hatchets tightened their schools and calmed down and the discus played a rousing game of PULL EACH OTHERS FINS OFF! The dominant discus went ham on his "daytime friends" pulling fins, chasing, the whole thing, which explains why the lower pecking order was getting beat up. And it took them no time to go at it either 5 minutes after the lights went off tops.

So why is this happening? If they're supposed to calm down when the lights go out why are they up at night fighting?

Could it be the moonlight? Come to think of it I didn't have this kind of aggression when it was pitch black. But plenty of people use moonlights and don't get "werediscus"

Also I have noticed the discus tend to pick on their own colors. I have 3 "wild types" 1 turquoise snake skin and one snakeskin pigeon blood. No one ever seems to mess with pigeon blood but the wild types are the ones always getting battle scars. Is this normal?

Discus are so weird. They are unlike any fish I have ever had and I have some weird fish. Does anyone have some great advice on this?

My discus get very active right after I turn off the lights as well, I too use a moonlight LED. My discus calm down and go to sleep within 5 to 10 minutes of turning on the moon lights. There is always that initial aggression but my group is large so there is not any damage done to any one fish.

I would be scared to not use moonlights for fear of the discus running into something and killing themselves.

[OC Discus]

I use a couple of night lights in the room where the fish are. Not bright enough to interrupt their sleep but not pitch black either. I don't think minor tail nipping by one discus to another is anything to worry about unless you see fungus or an open wound. The tip of the tail is like hair or finger nails I think- no nerve endings or blood bones. They can be trimmed and grow back.