Guppies seem afraid of new Tank mates

EDIT: 30.05.22
So, I am not sure if the tetra has/had lockjaw in the firdt place? Is there perhaps something similar to lockjaw? When we got him, his mouth was wide open and he could only move it a little bit. Now after a week of treatment, isolation and a clean hospital tank, his mouth can almost close again ( it's has improved about 80%), he even finally was able to eat today!

Hello there! ^~^

So, 2 weeks ago I adopted a 30litre aquarium from an older man who wanted to "get rid" of his aquarium and said if no one takes it, he'd flush his fish.

So, there I was with 6 fish in a way to small, NASTY aquarium. I don't think it was ever cleaned.
ANYWAY, I started with daily water changes, cleaned the gravel, changed the filter ( it's one of those swappable ones Form Tetra. The filter consisted of about 10% filter and 90% manure)
Treated the fish with some general fish medication to be sure, and upped the water temperature because it was under 20.

The 6 fish consist of : 1 Buenos aires tetra, 1 Mosaic Placo (Mosaik Panzerwels), 2 dwarf gouramies and a male and female Swordtail.

The buenos aires seems to be affected by Lockjaw, it's mouth is continuesly opened and he has not closed it once the past 2 weeks. He swims around with the other fish, there has been no visual sign of aggression.

I checked for compatibility, and except for the buenos aires tetra, everyone should be compatible.

2 weeks later ( yesterday) the fish have shown no signs of illness, so I introduced them to the main tank ( I DID read that buenos aires tetra are notorious fin nippers, but since he can't bite and most likely won't live long from what I've read, I thought I'd add him so A) he/she wasn't alone B) his/her last few days/weeks would be in a nice tank with his Mates, Plants, Room to swim and hiding spots.

Yesterday while we introduced the new fish, the guppies, who are VERY friendly and curious fish, went right up to them to inspect them, and everything seemed perfectly fine. The gouramies went right into hiding, the swordtail felt right at home, the Placo COULD NOT have cared less, and the tetra just went to the bottom into the plants with the gouramies.

A few hours later I checked on them, and the guppies were almost all together at the top of the tank, usually the swim around everywhere. There are a few males still courting the females and some of the larger females just go about their day like always.
The rest are pretty huddled together.


Today (8am) I checked on them again, and it's the same behaviors. When I put flakes in the tank, everyone comes to eat with no problem, but afterwards, everything return to the same spot.

I've watched the tank for about 1,5 - 2 hours straight now, I see no signs of aggression from the new fish ( I read gouramies can have a temperament), no one seems to be chasing the guppies, no fins are insured, the fry is still there.
The grouarmies occasionally swim through the huddle of groupies, but don't chase or nip at someone. The tetra just swims past them pretty much ignoring them, the Placo is VERY active and swimming around cleaning all plants etc.


Now, long story short, do my guppies, who have till now only known the one old timid Placo( Antennenwels) just need some time to acclimate to the new tank mates, or is something more serious going on? As mentioned, I have not seen any aggression, chasing or nipping.

It is THEIR tank and I don't want them to feel stressed.

Thank you in advance for reading my novel and taking the time to help!

With kind regards, Couwu

What is the tank size?
What are the water test results now all the fish are in?

I would isolate the Buenos Aries tetra in the 30 litre tank. Lockjaw can be a symptom of  TB tetanus.

The Guppies will take a week or two, maybe even longer, to find their feet and feel secure. They only arrived a short time ago, so everything is very new to them....think of it as the time you went to school for the first time ever, new surroundings and people, unsure about everything....give them a few weeks to settle in and they should be fine

The tank size is ~ 40 gallons, a 150l tank.
The water results are all fine, some of the guppies seem to not care to much and are swimming around as usual, just a larger crowd has gathered at the top, but come down occasionally.

Is TB tetanus? I read a little about it, but mostly you find the same few answers. Is it contagious to the others?

wasmewasntit said:

The Guppies will take a week or two, maybe even longer, to find their feet and feel secure. They only arrived a short time ago, so everything is very new to them....think of it as the time you went to school for the first time ever, new surroundings and people, unsure about everything....give them a few weeks to settle in and they should be fine

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The guppies have been in the tank for over 1 year, the 6 fish are the new ones. The guppies have been alone in the tank so far, so I am wondering if they are just intimidated by the new bigger fish?

TB = Tuberculosis and yes it is contagious...even to humans where the bacterium can be passed via open wounds on your hands and fingers.

It will still take considerable time for everyone to sort out their heirachy and territory, so I would not be too concerned about hiding or grouping....unless fights and injuries become an issue

Couwu said:

Is TB tetanus? I read a little about it, but mostly you find the same few answers. Is it contagious to the others?

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Sorry, yes that should read tetanus. It can come from dirty living conditions, like you described when you got them. The fish will be more comfortable in a "hospital tank" where it is not competing for food. As it doesn't have a shoal there is no advantage to keeping it in the main tank.

Okay, it took me quiet a bit, since my tank has many hiding places and plants, but I've finally cought and set the tetra into the hospital tank.

I would not be Suprised if it did end up being tetanus, the tank was absolutely HORRID.

Since the tank was not 100% done yet ( since all were in there till yesterday) I kept the tetra in a big bucket with water form his aquarium, cleaned the entire gravel thoroughly and filtered the water through a clean towel to get most of the nasty stuff out of the remaining water ( I only changed about 40% of the water with fresh water now. The rest was just filtered few times threw the towel and back into the aquarium)

When I got the aquarium, it had no plants and kid exorstion at all, just the 6 large fish. So I took one of the plants out of my main aquarium and gave the tetra a plant and some stone decoration. He should be feeling way better in the tank now (hopefully)

He IS actively swimming around

So seemingly he was probably the problem in the main tank after all. While I never saw him expect hiding, now that he is out of the main tank, most guppies have scattered around the aquarium again, which is a relief.

The photo shows the current hospital tank, the water is so milky because I just cleaned the gravel a few minutes ago and added filter medium. Usually it clears up pretty fast

Sounds good. Glad the guppies are better. Keep up the maintenance and cross fingers now.

Thank you!
The guppies eem to be feeling alot safer now, I appreciate the advice / help alot! <3

Well, joy didn't last long. The guppies were back huddled together today.

I DO Think I just now saw the orange gourmie chasing some of the younger guppies around. The guppies seem to be afraid of HIM (I think it is a male, the top fun is pointed, it's a Lager rather colorful gourami)

From someone with experience with these fish, does that usually settle after a few days, when the fish know boundaries etc, or is it something that could prove to be a problem? Like I said, I don't want the guppies to feel unsafe, this is their tank.

You should have rinsed the filter in de-chlorinated water, even if it was that dirty. Anyway, now you will have to go through a cycle which could take you about a month or a bit longer. Keep doing water changes.

Couwu said:

The photo shows the current hospital tank, the water is so milky because I just cleaned the gravel a few minutes ago and added filter medium. Usually it clears up pretty fast

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The fish in the picture in post #7 looks like a Beunos Aires tetra. These are renown fin nippers and if you have them in with the guppies, they might be trying to eat the guppies.

Colin_T said:

The fish in the picture in post #7 looks like a Beunos Aires tetra. These are renown fin nippers and if you have them in with the guppies, they might be trying to eat the guppies.

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It IS a buenos aires tetra, I am aware ^~^

He is currently alone in a hospital tank 1) because I don't know what he has 2) because he isn't suitable for the guppy tank.

I'm not sure if he would be physically able to nipp fins, as he cannot close his mouth 100% anymore, but it has improves since I got him few weeks ago and after few weeks of water changes, medication etc he has been eating finally.

Now he eats like any other healthy fish, which is a relief as he didn't eat at all the first week or so.

The guppies have acclimated to the other new dish, and are back to swimming around the tank as usual! Only took about 3-4days