is this normal ornate tetra behavior?

[Navfish]

I've had 4 ornate tetras since January and while they only fight sometimes, it isn't too extreme. But today when I saw them, they were doing some extreme chasing, and Idk why?


I have linked a video down below of their behavior today....can anyone explain why?

I checked water parameters and it seems to be okay (0 ammonia and nitrite)

However, there was a disease that spread in this tank so maybe that plays a factor.

 

[Slaphppy7]

A couple of males, sparring behavior, most likely caused by not enough members in the shoal

ALL tetras require at least 10 individuals of the same species, to spread out any aggressive tendencies, and for more natural behavior

 

[Byron]

Agree. There is no issue here, this is completely normal. They do however need a larger group, at least 10-12 minimum. The sooner you add another 6-8 of this same species, the better. And add them together at the same time, do not add 2 or 3, then 2 or 3 weeks later, etc. That is only asking for trouble. "Since January" I assume means earlier this month, so add the 6-8 (or more) ASAP. This will not cause "cycling" issues, before it is mentioned.

Also, you need some floating plants. These fish occur in veery shaded waters, and overhead light causes stress. Water Sprite, Water Lettuce, Frogbit, or a stem plant like pennywort left floating all work well.

 

[Slaphppy7]

What size is the tank?

 

[GaryE]

It's actually a sign of health, and of two males with a healthy dislike of each other.

 

[Slaphppy7]

It's actually a sign of health, and of two males with a healthy dislike of each other.

"Dislike", dominance-seeking, or a combination of the two

Regardless, the tank needs more of them, if the tank size is adequate....more females than males, optimally

 

[Navfish]

"Dislike", dominance-seeking, or a combination of the two

Regardless, the tank needs more of them, if the tank size is adequate....more females than males, optimally

Agree. There is no issue here, this is completely normal. They do however need a larger group, at least 10-12 minimum. The sooner you add another 6-8 of this same species, the better. And add them together at the same time, do not add 2 or 3, then 2 or 3 weeks later, etc. That is only asking for trouble. "Since January" I assume means earlier this month, so add the 6-8 (or more) ASAP. This will not cause "cycling" issues, before it is mentioned.

Also, you need some floating plants. These fish occur in veery shaded waters, and overhead light causes stress. Water Sprite, Water Lettuce, Frogbit, or a stem plant like pennywort left floating all work well.

I have a 37 gallon tank with
4x ornate tetras
2x mollies
1x juvenile angelfish

How many more should i get for this size?

And how do you tell if they are female or male?

 

[GaryE]

Sexing bentosi tetras takes a bit of staring. Look at your fish now, and note the height of the body. Females will be deeper bodied. With a bit of practice, it gets easier. Males will tend to be more streamlined, from dorsal to belly but also head on. They are more colourful in a good tank, but in a store you can't count on that.
The body shape difference is space for eggs.
The standard number is 6, but I prefer 10. In a perfect tank, having at least 4 males is good. A 3rd wheel can get picked on, but 4 or more makes for a spread out squabbling. They will always sort rank - when one wins, the challenges start all over again. If you have 2, one can be so busy losing it never gets to eat.

 

[Byron]

I have a 37 gallon tank with
4x ornate tetras
2x mollies
1x juvenile angelfish

How many more should i get for this size?

And how do you tell if they are female or male?

You have the space to increase the tetra species to 12, so that is your best bet. I have never bothered much about male/female when acquiring a proper-sized group of any characin, except for Congo Tetras. You will usually get both genders when acquiring a group. Even here, adding 8 to the 4 you have will likely result in a mix of both genders. But if you do think you can spot gender, my advice with this species would be a 50/50 mix. We are not dealing here with livebearers where the male(s) can easily harass females literally to death. With a species such as the Black Phantom (Hyphessobrycon megalopterus) the males will frequently have a split or two in the dorsal fin from their natural "play" but that is normal and not at all problematic. Numbers matter. A group of six will be under continual stress, whereas a group of 12 will not by comparison, and that means healthier fish.