Ember tetra missing eye

I woke up this morning to one less ember tetra, and another one missing an eye, and turning black (school is now 2 healthy ones, and 1 with a missing eye). They are in a 5.5g with a betta, which yes I know was a poor stocking choice on my part, but it worked out well until recently. I also was prepared to buy another tank to separate the fish out.

Before I did my WC this morning I tested the water and got 0.25,0,10-20 (ammonia, nitrite, nitrates) (its in the order the cycle goes if my label is not correct). I did the WC, and noticed the betta being aggressive towards the one eyed tetra. I then found a clean plastic tote, rinsed it out, and put the betta in there (I read somewhere this can help curb betta aggression). The 1 eyed tetra (sounds like some fictional monster) is now going back to his regular color, and swims around, and I think he even ate.

Now I normally wouldn't be typing this, but out buying another tank for the tetras. However in a week I am going (or will be) home for the holidays (which will involve a 7 hour drive, and as we are traveling leaving the tank alone for a week). I don't know if I am going to take any losses. I could lose all the tetras, making the other tank mute, or lose everything and start from square one. This makes me hesitant to buy a new setup. However if I don't lose anything, my current plan is to get a 5-10 gallon kinda planted tank for the tetras, and increase their numbers back up.

With all that out of way I am wondering what the best thing to do in the interI'm period before I get the new tank. There will be a picture attached somewhere on this post of the tetra. His color is coming back, is eating, and swims around like normal. I know keeping the water pristine is even more important now, is there anything else I should be doing. Also am I correct in assuming the betta attacked him, or could this be a disease?



Thank you

 

I'm sorry about your Embers.

More than likely the Betta attacked the fishes. Betta's are solitary fish and some work out but for the most part, need to be alone, as you discovered.

Is that any way you can "divide" the tank until you get your permanent arrangement done? Most hardware stores such as Orchard supply / Home depot sell plexI glass that they will cut for you. Or even a steel screen piece they can cut for you ( it needs to be the wire / steel cut that's thick to stand up )
I would personally go with the plexI glass so that the fish do not get hurt ( if the betta tries to attack thru the screen )

 

Their might be, I do live right behind a hardware store in an apartment full of engineering students. Its also where I got my mesh for the DIY lid I made. I might stop by when I have the time and look for good material for a divider. Although after putting the betta into the tank from his isolation he has left the tetras alone.

 

Update: The betta got a chunk out of the one eyed tetra. The tetra was gone by the time I netted him out and flushed him. If he wasn't I would of euathanized before I flushed

 

With a 5 gallon tank the betta really should be the only fish in there.