Problem with my tank

[Tiara]

Agree with above members, look for possible sources.

Definitely stop all the chemicals, this is certainly going to affect fish detrimentally. A basic conditioner that deals with chlorine/chloramine (if in your water), and heavy metals is all you need. The less chemical substances going in the water the better for the fish. I would also increase the weekly water change to at least 50%, up to 60 or 65%. Provided the parameters--these are GH, KH, pH and temperature--are basically the same, water changes can never hurt and may help, especially if there is something in the tank water.

The GH/pH is fine for these fish. Ammonia and nitrite are good (0), nitrates at 20ppm is higher than the fish will appreciate. Is nitrate in the source/tap water you use? Test it alone to see. Or is nitrate occurring solely within the biological system of the aquarium? If the latter,you may be overfeeding, not ding sufficient water changes, or overstocking. Numbers for a 70 liter (18 gallon) are not high but there are stocking problems I'll come back to. Are there live plants? These help with keeping nitrate low because aquatic plants grab ammonia/ammonium faster than the nitrifying bacteria, and the plants do not produce nitrite then nitrate as a result. Floating plants are best, and easiest.

To the stocking, this could be part of the problem. These barbs and tetras are shoaling/schooling fish, which in freshwater species means they live in large groups and they need decent-sixed groups in an aquarium. The species here, ignoring tank size and everything else, should have 10-12 for each of the barb species, and 12-15, preferably 20, for the rummynose tetras. This tank is not sufficient length for the rummynose, assuming it is no longer than 24 inches/60 cm (?). When the barbs especially are in smaller numbers, they tend to become more aggressive. This may be physical attacks, fin nips, etc, or it may just be allomones and pheromones which are chemical signals other fish read. Numbers really do matter. At the very least, over time insufficient will add more and more stress, leading to the aggression. Another effect is a latency to feed. Have you noticed any interaction at all between the fish in each species, or with other species?

Heya. Yo answer all of your question:
1. There are no nitrates in the tap water, probably they build up over time.
2. Yes- there are life palnts (forgot their names, because we have them since the start of the aquarium (with few changes here and there). We don't have floating plants, once I tried to put some, but the water flow is too strong for them. I can send pictures of the tank itself.
3 About the stocking- Yes, indeed these fish should be kept in large numbers, but I guess 6-7 are a maximum number for my tank. Just to mention that the Rummy nose tetras, since day 1, have very vibrant colours and red heads, and I red somewhere that this is a sign of happy fish. Also they swim very tightly and everywhere in the tank and have very good apetite.

This is not the case with the barbs, tho. Since we put them in the tank (around 1 year ago) they behave very shy- prefer to swim at night, mostly stay behind stones and plants, when they swim, they are kinda nervous and go back to their hidings spots, but had good apetite and came out when it was feeding time. They also had vibrant colours and were growing just fine. They have zero aggression towards each other and do not interact with the Rummy nose, except when they swim with them from time to time. Just to mention that the barbs have never been an object of aggression from any fish in the tank, which eventually may cause stress.

 

[Tiara]

Could there have been a contamination somehow? Aerosols being sprayed in the room? Perfume on the wrist or creams? Cleaning chemicals?

Anytime there's a suspected illness or the fish are unhappy, do a big water change. 50% or more. Always do a huge water change if there's a death in the tank especially if you don't know what's caused it

Hey. I wash my hands every time when I feed them or when I have to touch the water, we use perfumes in the other room, I don't know
Oki, I will change larger volume of water, maybe 50% until there are no more deaths in the tank.

 

[Colin_T]

pictures of the fish so we can check them for disease?

if you overdosed with medication, it could kill the fish.

 

[Byron]

1. There are no nitrates in the tap water, probably they build up over time.

OK, then you need to be dealing with this. Look at the feeding, and definitely larger weekly water changes. Plus some floating plants. You should be able to keep nitrates much lower, mine never rose above the 0 to 5 ppm range, over years.

As for the numbers...the barb description I would all but guarantee is due to small numbers. You cannot do much about this though, the tank space is limiting. But it is a reaction to the fish needing more of their own. The effects of too small a group is often aggression, but other times the reverse.

Rummynose are tight shoaling fish, the group will remain together basically always, except when feeding.

 

[Ram419]

there are life palnts (forgot their names, because we have them since the start of the aquarium (with few changes here and there). We don't have floating plants, once I tried to put some, but the water flow is too strong for them. I can send pictures of the tank itself.

I had same issue with floating plants. Get yourself a 3D printed baffle, worked great on one of my tanks. https://galaxyglowstudio.com/collections/filter-baffles

There's also this hack and use the under HOB filter method. -->

 

[Tiara]

pictures of the fish so we can check them for disease?

if you overdosed with medication, it could kill the fish.

I couldn't make good pictures, because the Rummy nose always move and the barbs hide. The quality,tho, is far from good.
p.s The water is a bit green. cause of the medication.
I don't think that anything can be said

 

[Tiara]

OK, then you need to be dealing with this. Look at the feeding, and definitely larger weekly water changes. Plus some floating plants. You should be able to keep nitrates much lower, mine never rose above the 0 to 5 ppm range, over years.

As for the numbers...the barb description I would all but guarantee is due to small numbers. You cannot do much about this though, the tank space is limiting. But it is a reaction to the fish needing more of their own. The effects of too small a group is often aggression, but other times the reverse.

Rummynose are tight shoaling fish, the group will remain together basically always, except when feeding.

Yes, I agree, probably they behave like that, cause of their small number. It seems that the minimum rule of 6+ fish from type is not the best option. They must be atleast 10 and up, but sadly no more space in the tank. if they continue to struggle, I will take them to the pet shop and will take Cherry Barbs instead, because they didn't show any sign of stress.

I wish I could afford a bigger tank, but there is no space in our room, sadly

 

[Tiara]

I want to thank you all, who gave me ideas and advises about the case.
I've been thinking a lot and got to a conclusion - The male barbs got sick probably cause of higher nitrates at some point and low imune system due to stress, and it was too late when I noticed it. (They always hide, when I'm near the tank).
The Cherry barb and the little Ancistrus probably died cause of the medication (despite the fact that I put as much as the instructions said) but it may have been strong for them.

So far everyone else seems fine. I will continue with larger water changes every week and hope that this will be enough.

Again thank you for your time and ideas! You are great!

 

[Colin_T]

The fish in the pictures look fine so it's unlikely to be an external disease.

At this stage keep doing water changes and hope they settle down. If anymore look or act unusual, get videos and photos on here asap and we look into it further. Videos can be uploaded to YouTube, then copy & paste the link here.

 

[Tiara]

The fish in the pictures look fine so it's unlikely to be an external disease.

At this stage keep doing water changes and hope they settle down. If anymore look or act unusual, get videos and photos on here asap and we look into it further. Videos can be uploaded to YouTube, then copy & paste the link here.

Oki, thanks for the advice. Sadly the problems do not end here.
Since yesterday morning, the biggest Rummy nose tetra (they are 2 which are big) out of nowhere decided to claim the whole tank for herself, so by the end of the day all the other tetras began to stay only in the corner. Whenever they want to go to her, she chases them away around the tank, so they gave up.

I'm so sad now, because they were swimming together all this time and the smaller tetras are noe wondering why they are chased away ... I will put away the fish for some hours and will put her back in. I don't think this will solve the problem, but at least I can try.

The good news is that by the end of this month we will get a bigger tank, not much bigger, but still.

 

[CaptainBarnicles]

Aggression in schooling fish is usually down to the group not being big enough...Rummynose love to live in huge numbers, the bigger the better. I know that you are limited with space but do try to get the biggest (longest) tank that you can afford or have physical space for. Rummynose are extremely active and need space to swim and dart around, and if you want to keep them without problems you'll have to increase their numbers.

If you can't give them that then I'm afraid you may find that they'll get ill due to stress and or be picked off one by one by the most dominant among them. Perhaps you should consider rehoming them and increasing numbers in your barbs instead?

 

[Tiara]

Aggression in schooling fish is usually down to the group not being big enough...Rummynose love to live in huge numbers, the bigger the better. I know that you are limited with space but do try to get the biggest (longest) tank that you can afford or have physical space for. Rummynose are extremely active and need space to swim and dart around, and if you want to keep them without problems you'll have to increase their numbers.

If you can't give them that then I'm afraid you may find that they'll get ill due to stress and or be picked off one by one by the most dominant among them. Perhaps you should consider rehoming them and increasing numbers in your barbs instead?

Yes, everything you mentioned is just right.

I will wait until we move them in the new tank and will buy 2-3 more fish, if then things do not get better I will give them away.
It's just ....they have been this number since around 1 year and they were always together, they are not a new group so they fight for territory....
At least the problem with the sudden deaths stopped....

 

[CaptainBarnicles]

It's not a territory issue as such, it's about safety and hierarchy if I'm not mistaken...perhaps someone can explain better...

Because there were more fish to start with, even though the RN were small in number, they felt safer together....but now that you've lost some fish, the dynamic in the tank has changed which in turn affects the way the RN behave

 

[Tiara]

It's not a territory issue as such, it's about safety and hierarchy if I'm not mistaken...perhaps someone can explain better...

Because there were more fish to start with, even though the RN were small in number, they felt safer together....but now that you've lost some fish, the dynamic in the tank has changed which in turn affects the way the RN behave

Oh, I see. By the way I'll change the water today, so I cut some of the grass, so they have more space to swim in the open, and so far the Rummy nose stopped chasing the other fish.
I will also buy 2 male barbs, because now I have only females.
If things get like they were before I won't do any changes until we move them in the other tank.

And sorry for spaming the threat, but every day something new comes out

 

[CaptainBarnicles]

You must keep doing your water changes every week