Sudden Change In Fish Behavior Overnight

[vasu4ual]

Hi everyone,

So just yesterday my fish were all swimming around happily in my 29 gallon planted tank. I got this tank a while back, cycled it for two to three weeks, and just added the fish two weeks ago. The fish I had were:

6 guppies from my previous tank, which was running for four months
2 platies from the same previous tank
1 more guppy from the store
5 peppered cories from the store
Along with 2 nerite snails and 3 MTS from the store

The fish were doing fine until just this morning; the guppies/platies usually kept to the sides of the tank because the current in the center was pretty strong, and the cories just hid out in the back. I was taken completely by surprise because just this morning I came to look at the tank and found two of my original six guppies dead. This shocked me because they showed no signs of illness or fatigue the night before, and I immediately removed the fish and topped off the tank with water. I continued to monitor the tank for the day and noticed more; the other five guppies all suddenly started acting lethargic too. One of my males sunk to the bottom of the tank and has been sitting there gasping all day, and the other male is swimming at the top almost vertically. The smaller female sits still next to the heater, and the other two guppies sit still for a while then swim around. The guppies' gills are red on the inside, and all day they've had long, stringy poop (some red, some white) hanging off of them. One of my platies is also being a bit strange. He's the submissive one out of the two, but as of today he's been hiding more often in the bushes and is now also at the top of the tank slanting slightly, with stringy poop out of him too. The cories and other platy are doing fine, as are the snails. I moved the two males (one sitting on bottom and one swimming vertically) into a mug temporarily to monitor them closely.

I used marineland test strips to test my water and the parameters are:
Nitrate 40ppm
Nitrite 0ppm
Hardness 300ppm (I have pretty hard water in my region)
Chlorine 0ppm
Alkalinity 80ppm
pH 6.8-7.2

I don't add any chemicals into the tank except for API CO2 booster (1mL everyday) and TopFin water conditioner whenever I top off the tank. I feed the fish twice every day with a few flakes, though last night I may have poured in just a little too much.

My test strips don't read for ammonia, which could be a problem but my snails and cories aren't behaving strangely. I thought it might have been an issue with the strong current tiring the fish, but that still doesn't explain a sudden shift in behavior or the two deaths. My final hunch is a parasite, but I don't want to medicate until I'm sure of what the problem is.

Does anyone know what could have killed my fish and caused them to suddenly start acting lethargic?

 

[vasu4ual]

UPDATE:

I just checked on all the fish and the ones in the tank seem to have recovered. They're swimming around now and they don't stop at the surface as much. The two fish I quarantined definitely have a swim bladder problem. They keep falling upside down and sideways only to struggle up again and try to swim. I have a feeling neither of them are going to survive the night... why did my fish suddenly start having issues?

 

[GobyMaster11276]

UPDATE:

I just checked on all the fish and the ones in the tank seem to have recovered. They're swimming around now and they don't stop at the surface as much. The two fish I quarantined definitely have a swim bladder problem. They keep falling upside down and sideways only to struggle up again and try to swim. I have a feeling neither of them are going to survive the night... why did my fish suddenly start having issues?

If you overfed, it's likely high ammonia. It may also be because they overate, which can cause issues. Do they eat at the surface? That can cause swim bladder issues, so you should lower the flakes below the water. Let them fast for a day or two, then feed them finely crushed, peeled peas. You may want to consider getting some Epsom salts (that's what I was told to use by a friend anyways) to put in, but most likely they won't survive. Swim bladder is quite hard to recover from (from my experience and what I've heard anyway). Good luck.

 

[Mrscmurray]

I would also get a test for ammonia, that's a lot of fish to add all in one go to a newly cycled tank so it could be that it's spiked

Sent from my HTC Desire 626 using Tapatalk

 

[hobby5]

Did you check your water temp?

 

[**sarahp**]

cycled it for two to three weeks

How exactly did you cycle it? A fishless cycle generally takes longer than two or three weeks. If it wasn't properly cycled then that could account for the issues?

Also how often and how much water do you change??

 

[vasu4ual]

I don't change water that often, about once every week or two weeks. I seriously doubt that the cycling/ammonia is an issue because none of the other fish in my tank are affected. The cories hide during day but become really active at night, and the platies swim around regularly. The snails aren't climbing up the walls either.

As of today, all of my original guppies have died except for the one I bought from PetCo, which is swimming around a little more actively. I suspect either a parasite/disease hit all of these guppies (they were from a friend's tank and maybe aren't as resilient as store fish??) or they just became very stressed from the move/stronger filter current.

The red gills, slight bloating, and swim bladder disease seem to indicate ammonia/nitrite, but because none of my other fish (not even the store bought guppy) are dying in a mass pandemic, I don't really buy it.

 

[Byron]

A couple of general observations.

First, guppies are not at all hardy fish these days. Decades of inbreeding is believed to have severely weakened this fish's resilience. Unless you obtain wild caught fish (extremely rare), or you obtain fish from a breeder using wild stock, you are getting genetically weak fish.

Second observation is that so many fish problems have similar if not identical symptoms, externally. Reading through this thread, one thing that occurs to me is some internal protozoan. I had something once that caused this swim bladder problem in rummynose tetra, and a microbiologist friend told me this is not surprising. Without dissection of dead fish by a trained biologist or microbiologist, it is impossible to pin point internal protozoan, but they are one option.

If whatever this is does not spread to the other fish, you are indeed lucky. That might suggest some generic issue in the guppies, but not a certainty. When fish are introduced to an established community of other species, it is possible for the new fish to be "attacked" by something the existing fish have managed to circumvent (think of it as some form of ammunity). The reverse can happen too, obviously, which is why you should quarantine fish from another aquarist just as much as fish from a store. I speak from sad experience, having lost half a tank of fish twice to some unknown protozoan. And it can take weeks for something like this to be observed even in QT.

Byron.

 

[Ch4rlie]

First thing I've noticed is your alkalinity reading of 80ppm, this is soft water so that sorts of corresponds with your readings of pH of 6.8 to 7.2. But this contradicts against the 300ppm hardness reading you gave in your first post. 300ppm is very hard water.

One of these readings is wrong, imho.

So I would advise either getting your local water authority website readings and gettng a liquid based test kit, API Master Freshwater kit is not bad and a lot of members of this forum uses this. And double check your test readings against your water authority website.

Guppies and platies are hard water fish, as is most livebearers.

This may explain why your guppies dying but the cories are fine since they are softwater species.

 

[vasu4ual]

I have a layer of peat moss below my substrate which could be the explanation for the pH reading.

 

[Byron]

I have a layer of peat moss below my substrate which could be the explanation for the pH reading.

I just answered this in your other thread, so I will repeat it here. Generally, having one topic in more than one thread can get confusing, so be careful.

Yes, I believe so. The KH acts as a "buffer" to prevent pH fluctuations, and often it will counter in a sense the effects of organics (peat, wood, leaves and fish food/excrement are all organics). But here is the KH is not high, at 80 ppm (4 dKH) so peat I assume would have more effect. However, at some point the peat will exhaust itself, and then the pH will rise. Out of curiosity, what is the pH of the source water? I have been assuming the GH and KH were source water levels, but if they are aquarium, there could be substances therein that affect these. It might help clarify if you could post the GH, KH and pH of the source water (tap presumably) on its own, and then the same test levels for the aquarium water.

Remember when testing tap water for pH to out-gas the CO2 or it could affect the result. Letting a jar of water sit 24 hours is one method, another is to briskly agitate it for several minutes.

Byron.

 

[GobyMaster11276]

What is your ammonia?