School’s in!

In the days of angle-iron frames and putty to seal the glass, I got a 1.2 metre x 60cm x 60 cm fishtank. I thought I was made. I haunted the aquarium shops looking for pairs of as many different fish as I could afford. Not that I was planning on breeding them, that’s just the way I wanted it. Probably I couldn’t make up my mind about which species I liked best.

Actually the first fish I ever bred was a red platy. When she was ‘due’ I put her in a little plastic container, about 100mm square at the top and 20cm deep. I knew that she was likely to eat some of her fry, so Mum offered to cut a section of her bridal veil so that the fry could hatch and escape their mother’s attention! The 11 resultant fry were very carefully nurtured.

Fast forward about 60 years and my focus has changed a bit.

Oh, but hang on a bit. In the mid 60’s I got a job working in Fred Parkes’ shop over the Christmas holidays. They had fewer species then than are available now, so the selling tanks were often one species to a tank. For some reason or other they had 30 or 40 red-eye tetras in this one tank. It was a case of perpetual motion, swimming around and around the tank in a tight school. I was fascinated and intrigued. The only other fish that I remember from that time doing a similar thing was the golden barb.

        
As you’ve probably guessed, all those years later, my current focus is on finding good schooling fish. (This interest has nothing to do with my previous occupation {schoolteacher}.)

I’m sorry about this, but I have to get pedantic for a moment.

Many people use the terms schooling and shoaling interchangeably, but that’s not accurate. For the proposes of the home aquarium:

• Schooling fish group tightly together and often all swim in the same direction together. 
• Shoaling fish group loosely and don’t usually swim in the same direction, but they still like others of their kind close by. 

An example from all that time ago was a tank of cardinal tetras in High Street St Kilda. It was a pretty dark 3’ tank towards the back of the shop. It featured Java fern & just enough light to show off a mass of cardinal tetras. There must have been over 50 of them, in the days when cardinals weren’t cheap. It was so spectacular.

I wonder if we haven’t got caught up a bit with the new and exotic, whereas some of the old can be nothing short of spectacular.

The key then is that we’re looking for fish that move as a unit together for most of their waking hours.

So back to the present.

A few questions present themselves:

• What species (that are suitable for a community tank) will school?
• What’s the minimum number of fish to school well, (or at all)?
• Is there a pattern to who leads the school direction and speed?
• Is there a minimum tank size for them to school in?

I’m not saying I only want schooling fish in my tank, but one or two really active species is what I’m after.

To complicate matters further, I want just Amazon fish. No reason, except that our Melbourne water is soft, and this set-up started with discus. Maybe, just maybe, they might make a come-back?

So let’s start with fish that are good schooling fish, but are not Amazon fish.

Good schooling fish

Barbs

• Golden barb
• Tiger barb. A school of 10 or so tiger barbs is a great sight.
• Sahyadria denisonii  (Torpedo Barb). Patrick told me that when it came time to top up his school of the Torpedo Barb, the older bigger fish swam in one school and the smaller in another. They eventually amalgamated when the younger got a bit more size.

Catfish 

• Ghost glass catfish

Danios

• Zebras, pearl, leopard, etc
• Giant danio types

Loaches

• Clown loach. Even small clown loaches school well, but they do hide a lot and grow big when you’re not looking.

Good shoalers (including Amazons)

• Pencilfish
• Brown-tailed (N. eques).

Rainbows

• M. wilsoni (Darwin mccullochi) with fredericki; lacustris and luminatus
• M. praecox
• M. lacustris. Patrick’s experience with these fish is that they shoaled nicely in a 1.2m tank, but when transferred to a 1.8m tank they schooled nicely.

Rasboras

• Harlequins
• B. maculata
• scissortails

Tetras
 

• Bleeding Heart
• Bloodfin
• Buenos Aires 
• Cardinals
• Congos
• Ember 
• Glowlight 
• Hatchet fish
• Hockey sticks
• Lemon
• Red-blue Columbian
• Rosy
• Phantoms: Black, Red, Yellow 

 
Just a note on a couple of these:
         
I have seen a school of Hockey Sticks, (the common ones), in a very tight school about the size and shape of a tennis ball. I think they need more than 6 to form a school though.             

The bleeding hearts in my tank shoal in an unusual way: they’re in the open water close to the front of the tank, and nearly always in exactly the same format. Most of them are facing into the (mild) current while one facing the opposite direction in the front of the shoal, and 2 facing the opposite way at the back of the shoal. There is usually a smaller female out of the shoal to the left but out of the picture. Try to catch them though, and they disappear very quickly.

I can’t explain why a small school of rummy nose are so high up in the corner: unusual.
  

Larger fish (for larger tanks)

• Silver dollars (body size gets 150mm)
• Silver sharks (usually up to 30cm)
• Tinfoil barbs (<35cm)
• Clown loaches (usually <30cm)
• The Mascara barb, Dawkinsia assimilis
•  is a larger fish (<12 cm). but a good schooler  
• and quite pretty’

Shoalers: 

• Cardinals, neons
• Black widow tetras
• Veilfin tetras          
• Veilfin tetra    
• Emperor tetras
• Some rainbows

Corydoras hastatus Apparently the Cory hastatus and the Veilfin tetra (Hyphessobrycon elachys) have been found schooling together in the wild.

  

Territorial fish:

Just to put the other side of the coin: there are tetras that are very territorial: for example:

• Paraguay tetras         Aphyocharax paraguayensis.

Incidentally, note the similarity between The two species above and the Paraguay tetra.

The ‘predator effect’. Many species that don’t normally shoal or school, (e.g. Angels), at least in small numbers, when they feel threatened, may readily shoal. If I’m doing some shifting around rocks or plants in my tank, the angels would shoal very tightly up the other end of the tank.

Some examples of fish that just don’t school

• Otocinclus
• L number catfish
• Mzueli or red cherry tetras, Hyphessobrycon “mzuel”. These are a new, brightly coloured tetra that are very active, chasing each other around individually, without doing any harm. Yet.

The current situation at my place February 2025. 


Actually things are a bit different to the photo. The angels have been moved elsewhere. The shoal of neons kept getting smaller and smaller.

At the moment I have about a dozen rummy-nose tetras that sometimes break up into two or 3 groups that then make their own way up and down the tank. They seem quite happy to school with just 3 or 4 fish. There are 6 diamond tetras that occasionally see the need to go quickly up the other end of the tank. A few phoenix tetras join in sometimes, without really seeming convinced that they should be there.  

 

Diamond      Phoenix

Ideally, I’d like to get a few more diamond tetras, just to make their movement a bit more of a spectacle. And harking back to those earlier days: a school of 20 or 30 red-eye tetras to see if they still move as I remember them.

So some of my conclusions:

• It may be better to have greater numbers of fewer species
• With most species, the more fish you have of that species, the better the school works
• There are very different types of behaviours from one species to another, even within the same family
• Size of the tank can be a determining factor as to whether fish shoal or school
• Not everyone shares my fascination with schooling fish. One of my friends almost has a blood-pressure event when watching the “perpetual, pointless motion”.
• This isn’t the definitive list of schooling and shoaling fish. Just a start really.

Cuz

P.S. At the club meeting (February ‘25) I bought 6 Aspidoras spilotus. They often spend a lot of time together, with quick random movements, darting in all directions at once, usually just a few centimetres above the gravel.

I haven’t seen a common name for them. Can I suggest Chaos Catfish? I’d like to get some more, just to see if the chaos continues with greater numbers.