Increase tetra shoaling behavior by adding larger fish?

[strawtarget]

I read somewhere that small community fish (mostly tetras) will shoal more tightly / more often if there are larger fish in the tank with them.

Is this the case? How much larger would the other fish have to be?

Any suggestions? (I'm planning a planted 55 gallon with cardinal tetras, harlequin rasboras, and panda cory cats.)

 

[Coleallensmom]

I can't say if this is true or not. I recently added a Gourami to my tetra tank and I've not noticed any changes in the amount of time spent shoaling. I'm sure if it was a somewhat agressive larger fish that might be true since tank enviroment can affect shoaling. All of my tetra shoal more often when we have company/the noise level rises in the house or if they see people hanging around the tank too long, but IMO that would be because they are uncomfortable which isn't necessarily a good thing.

IME, certain tetra do shoal more often then others i.e. My Black skirts swim together far more often then my Pristellas. When my pristellas do shoal, it's normally because they've decided to discreetly follow the black skirts around. On the other hand, I've never once seen my Black neons (I have 6) swimming in a group larger than three.

That being said, Cardinals are very colorful and IMO look amazing when the shoal together in a large group. In a tank that size, I'd totally go for a group of 12+.

 

[tyspot1000]

Schooling is a defense mechanism that wild schools / shoals do in the wild to make them look bigger to other predators.

Like Coleallensmom said, It really depends on the type of tetra. Yes they will possibly school when they enter the aquarium the first few hours, but once comfortable, they will spread out.

Ive had my neons school more than my harlequins used to, The harle's only did when I was doing a water change