I haven't had but a few nano-species of tetras.

But, the ones I have had have all been good schoolers. The important thing to get characins to school tightly is to get as large a school as possible. If the numbers are not adequate they will not express this natural schooling behavior because of stress. In nature, the smaller the tetra, the larger the school is in numbers. This is the :safety in numbers: behavior. In other words, if you were thinking like a nano-fish, the more fish around me, the less likelihood I will be the one eaten.

In a 20 gallon I would get one type of nano fish and put at least 24 of them.
But, since you are set on two varieties, some of this tight schooling behavior will be diminished as the two schools meet in the aquarium. Get at least 12 of each species. This should be the starting point for a proper school of nano-fish.

These are the ones I have had in larger numbers that have schooled well:
Neon tetra Paracheirodon innesi

Green Neon Tetra Paracheirodon simulans

Tucano Tetra Tucanoichthys tucano I have these currently, they didn't start schooling until I got 12 of them. I have slowly been putting these in my aquarium as I have had a hard time acclimating them. These need low hardness and soft water conditions. The most beautiful nano-fish I have ever seen.The last shipment was 100% survival rate. I will get another 12 in the coming weeks.

 

Hi, i'm so sorry. I should've been more specific. I already have kuhli loaches and shrimp for the bottom and was looking for one schooling fish for the top. I'm considering ember tetras but I still haven't made my mind up yet. I'm still researching other fish.

I have always loved neons, regardless of their "beginner" fish status but am nervous of "neon tetra disease" although I don't know much about it.. just that the fish will die. :confused1:

 

I vote for green neons over standards. They're smaller so you can have a few more if you want. They shoal nicely, and tend to form a tight school in my tank after feeding. Other times, they just kind of hang around in a group waiting for current to bring things their way. I find that a bit boring so I added a group of 12 ruby tetras and while they rarely school, they are always exploring the tank. Ruby tetras are my favorite small tetra by far and adding them has made the 17 green neons I have much more outgoing, especially at feeding time.

 

If you're worried about neon tetra disease, cardinal tetras are always a good option. They do reach a bit longer than neon tetras, but look similar, and I don't think the length will end up being a huge issue.

 

I’m a big fan of:
Danio tinwini (gold ring danio)
Loreto tetras (cheaper similar version of Tucano)
Rummy nose tetra
White Cloud Mountain minnows
Fire ember tetras

I’ve kept all of those in varying numbers. The tinwini are by far my favorite.

 

I’m a big fan of:
Danio tinwini (gold ring danio)
Loreto tetras (cheaper similar version of Tucano)
Rummy nose tetra
White Cloud Mountain minnows
Fire ember tetras

I’ve kept all of those in varying numbers. The tinwini are by far my favorite.

I've been dying to get my hands on tinwini for years but can never find a seller. Where do you get them?!

 

I have a school of Espei/lambchop rasboras in my small aquarium and they school very well. Very brightly colored too, almost like they have a light inside them.

 

Rasbora -

I just put a school of 6 chili rasbora in my nano tank with some RCS - all good!

Paul

 

I am also a fan of the chili rasbora, and they are so small that you could have a huge school of them. I also have enjoyed green neon tetras.

 

A large number of dwarf pencilfish would go well in that tank.

 

Brevibora dorsiocellata is one of the more underrated fish IMO. They're sold as Emerald Eye rasbora or Eyespot rasbora and although they don't offer much color in their bodies, their eyes sparkle green in the light. (NOT to be confused with Emerald Dwarf Rasboras which I've also kept and found pretty worthless)
I've had my current group for over a year, and here's a few things I like about them:
They keep the tightest school of any fish I'VE kept
They stay small, my biggest oldest females barely break the 1 inch mark
They are always in the top third of the tank
They eat well and I've not had any get sick
They allow my dwarf shrimp colony to grow (unlike other nano fish that have decreased shrimp populations for me ...like the darned Emerald dwarf guys)
They are in my 29 with only Otto cats and neocaridina shrimp so their schooling behavior is not just a defense mechanism from larger fish

 

Everyone has made some good recommendations! I mostly came here to say thanks to KayakJim for highlighting this species. It is on my list to keep once I setup an Indonesian biotope, and being pretty cheap, you can't go wrong. I've loved what I've seen from them in the shop, and it's great to hear from someone's long-time experience that they act the same at home.

My favorite nano fish include Tucanos (echo what Discusluv says - fewer than 10 and they shoal wherever, more than 10 and they school usually), Pencils, oddball tetras from South America (varies by vendor but just find a vendor you like and ask what they have), Neolebias trilineatus are a new one I've seen that I have fallen in love with, etc.

 

I have a group of ember tetras. They school nicely and are beautiful.

 

I have Hyphessobrycon elachys Hyphessobrycon amandae together in a 40g and the H. elachys (reed tetras) are much better schoolers that the H. amandae (ember tetras). The ember tetras do sometimes often group up together as well though. If you want to see the best schooling behavior though the bigger the tank the better IMO.

 

So i've narrowed it down to espei rasbora, harlequin rasbora, or ember tetras. I'm looking to get 10-12 of either one. What would you guys choose/what would look best/have the best behavior? I have a planted tank with lots of deep green plants and brown sand. I have kuhlis too.

1. I would have to order in the espei rasboras from my LPS
2. My LPS only has 5 harlequins left and would have to order more or get them at Petsmart (which take great care of their fish in my area.. maybe more so than my LPS)
3. 20+ Ember tetras are currently at my LPS, looking great but not that colored up

Here is my tank, it looks better in person. I just don't have the sharpest phone camera.

 

I have 10 embers in a 20 long and they do swim as a group although not exactly a "school." One thing that seems to help is the presence of a larger, more aggressive fish (in my case, a lone Black Molly).

 

All signs point to ember tetra. You've liked them since post #1, and you maybe have the ability to pick the best 10-12 from the group

 

I love my ember tetras, they're one of my absolute favorite fish. I've got probably 30? in my 33 long (along with furcatas, sparkling gouramis, pygmy cories, and a few guppies). I will say, they didn't necessarily school real well when I only had a dozen or so, but they do stick together relatively well in the bigger group.

 

Realistically you can add a ton of ember tetras. While your aquarium is smaller, ember tetras have a small bioload and the 1" per gallon rule kind of breaks down with smaller and larger fish. For example 9 ember tetras doesn't have the bioload of 1 6" goldfish.

You will have to add more ember's to have them school, but you do seem to be a huge fan of them. I'd recommend starting with 10 or so and seeing if they school. If they don't you could probably comfortably add 10 more.

Also, I just want to add, your aquarium looks great.

 

I'd pick embers or espei. I'd say the espei probably have the edge over embers in terms of tightness of schooling, but I just like the embers personally. What you see in the shop is nothing to what they can colour up to.

When they are happy they are a stunning colour. Here are mine, and that's what they look like in real life no photo manipulation.

 

I'm going to the store tomorrow to see if they have any espeis. If not, i'm choosing between the 12 embers or 10-12 harlequin rasboras since i'm able to get them without ordering in this bitter cold (-10 to -20c overnight).

Just wondering what you guys know about the lifespan or embers/harlequins and if there's a big difference? Ideally I would like a fish that lives long.

 

I'd say about the same. Keep them well and they can easily live 5-7 years and some will push up toward 10.

 

Take your time, no rush Ask your LFS about ordering you some in if they don't have them in stock. They often have a lot more fish available to them than they actually keep in stock.

 

Kind of bummed. In the summer my LPS had gotten their tanks taken out and new ones put in. Every time I go in things look worse. There was a lot of dead fish in the tanks today and one ember tetra that I spotted had a bacterial infection (raised, fluffy white patch).

Went to Petsmart and the tanks were crystal clear and no dead fish.

 

Well, I went to Petsmart and I was going to get Harlequins.. took a very close look for a few minutes and 3 of them had a little fluff on their bottoms lips that was barely visible. No thanks.

Went to my LPS to check out the Embers again and the one with the "suspected" bacterial infection was no different and the other 20+ were fine... so I picked up 10 Embers. We will see how they do in QT. I got a deal on them too.

 

Good luck - I do like my ember so hope they turn out well for you too!

 

They are very cute and are starting to color up already. I love how they try to eat little particles in the water. I might pick up 6 more after this batch is quarantined.

 

Harlequin rasbora

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