Amount of fish for middle of the tank

Loulou73

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Hi all, just wondering what people's thoughts are on how many schools of tetras to house in 140 litre planted tank. I currently gave 10 neon tetras, who were swimming very calmy at the beginning, they were the first fish I got. After a week I added 6 black eye tetras, both schools stayed within their groups. Then a week later.... added 6 rummynose. 1 died overnight. However, last few days the groups are all intermixed, darting more. They look like fish on speed! Have I overpopulated the middle region of the tank? Looks a little messy. Also have a bristlenose and golden gourami ( who hides most of the day, doesn't bother tetras). Ph 7.4, ammonia 0 - 0.25 and nitrate 0.5.
Will enjoy hearing people's thoughts 🙏
 
I know that if (when) I get myself a really big tank, I'll be filling the middle water with shoals of tetra and will struggle to restrain my choices.
Back in the day, it was often recommended to get two of each tetra the shop had...then it was realised that tetra need to be in groups of their own kind, in order to thrive.
Throw in better knowledge about the optimum water and we've moved on a tad.

But consider this...shoaling fish shoal for protection and so, especially in a more stress-full tank, disparate species may shoal together. This is also demonstrated by the acknowledgement of the role of 'dither' fish.

I have a 100 litre tank, with small shoals of glowlight and black neon tetra, golden pencilfish and pygmy corydoras and another with copper harlequin, chilli rasbora and cherry barbs.
Occasionally, they'll shoal together, but, more often than not, they're spread throughout the tanks, maybe in small groups of three of four, sometimes in just pairs. Only the copper harlequin seen intent on staying together as a tight group and it is only these that school together, flowing from one part of the tank to another.
 
Can I just check that you cycled your tank properly before adding fish? Any ammonia in a tank means something is going wrong. A water change will help stop ammonia doing as much damage but if it was there in the first place something is not right and needs to be fixed.

Back to the original question though tetras are absolutely my favorite freshwater tropical fish. As Bruce said if they are feeling safe they will often go off into smaller groups and only shoal back together if they feel threatened or when feeding. This is pretty normal for most (maybe all?) species of tetra.

Definitely not overcrowded in terms of swim room. What are your tank dimensions?

I would suggest once you figure out your ammonia issues that you get 3 or 4 more rummy nose tetras as 5 is a bit too small of a group for them.

In a tank that size you could probably be fine with about 3 largish groups of tetras.
 
Fish charging around as described might be a water issue, or fish, or light. What are your water parameters (GH, pH, temperature)?

What species are "black eye" tetras?

The "golden gourami" presumably is a gold gourami, a variety of the species Trichopodus trichopterus, one of if not the most aggressive of the small/medium sized gourami. A single fish has been known to eat tetras easily, and kill every fish in the tank. You may not see evidence, but it may still occur, something to be aware of.
 
Fish charging around as described might be a water issue, or fish, or light. What are your water parameters (GH, pH, temperature)?

What species are "black eye" tetras?

The "golden gourami" presumably is a gold gourami, a variety of the species Trichopodus trichopterus, one of if not the most aggressive of the small/medium sized gourami. A single fish has been known to eat tetras easily, and kill every fish in the tank. You may not see evidence, but it may still occur, something to be aware of.
Thanks for the advice.
Oops... so that should be red eye tetras! Did I just invent a new species! 🤦‍♀️
Has the LFS given me dud info on being able to have a gold gourami in with neons? I asked for a suitable feature fish and I was told this one would be fine. Do I need to remove it?

Water parameters. PH 7.4
Don't test GH ( How does this affect fish ? )
temp set at 26 c
Cheers
 
Thanks for the advice.
Oops... so that should be red eye tetras! Did I just invent a new species! 🤦‍♀️
Has the LFS given me dud info on being able to have a gold gourami in with neons? I asked for a suitable feature fish and I was told this one would be fine. Do I need to remove it?
Probably. The shop saw you coming.
Don't test GH ( How does this affect fish ? )
GH (General Hardness) relates to the mineral content of the water. You may have heard references made to 'hard' and 'soft' water. This is important, as many fish can only tolerate or thrive in one or the other.
This can also influence pH.

You need to do some more reading. ;)
 
I'll bring this back on track. I don't like tanks with lots of different species, if you you want to keep lots of species get more tanks. I like a tank that has, Two schools of Tetras or Rasboras or Barbs or what ever. So 20 of each fish. Then something that catches your eye on the surface, a Gourami or Butterfly fish, then something that drags your eye to the bottom of the tank, Corydoras or whiptail cat or bristlenose or a loach or two.
 
I have to agree with this. years ago I was in the "minimum number of lots of species" camp, now I'm in the "lots of a few species" camp.
 
The GH is very important, as others have noted. Generally, the GH of your source water will remain pretty much the same in the aquarium, so regular testing is not necessary once you know what it is to start with. You municipal water authority might have this posted on their website, or could tell you if you call them. GH is general hardness or total hardness, which is the measure of the dissolved hard minerals, primarily calcium and magnesium, in the water.

The Gold Gourami is going to be problematic, depending what you intend for other fish. Never trust fish store advice without research.

The Red Eye Tetra is the species Moenkhausia sanctaefilomenae and will be OK but with a larger group. It is an active fish, which is not good with sedate fish like gourami, so another issue there.
 

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