Two days ago I purchased 6 Glowlight Tetras for a new, fully cycled 10 gallon setup (I am not going to go into all of the details here, but the cycle is established and ready for fish). My tank had 5 small plants and 1 male Platy (see tank details below).
I watched the potential fish for about twenty minutes at the store. There was a group of 8 active Glowlights shoaling wonderfully and then a seemingly separate shoal of 5 Glowlights on the other side of the tank that seemed less tight. All seemed healthy as were the other fish in the tank. As my tank is only a 10 gallon, I took 6 smaller Glowlights from the shoal of 8. I wished I could have taken all all 8, but did not want to add so many at once.
Three hours after acclimating for 75 minutes (15 minutes floating the bag for temperature, 60 minutes of slowly adding water to the bag), one of the fish had died. The next day, another one died. Not so surprising as two of the six seemed more stressed after the move. The dead had no visible blemishes or indications of disease.
The remaining four seem very healthy, are eating actively and are impressively staying in a tight shoal. That said, I am not sure I want to replace from the same stock where only 66.7% survived.
Here are my questions to those of you with experience with shoaling/schooling tetras:
(1) Have you found tetras of the same species will readily shoal if they come from different sources (different pet stores, breeders, etc.)?
(2) Has anyone had success in a small tank with tetras continuing to shoal well in low numbers (like the 4 I have)?
(3) Is my best bet to go to the same pet store where I bought the originals and add more Glowlights to the group?
Thank you all for your help. Any advice on Glowlight tetras is welcome.
Using the API Freshwater Master Test Kit
Standard 10 Gallon Tank
Aqueon Deluxe Full Hood, 20" (with 18", 15W, T8 Full Spectrum Bulb)
Top Fin Aquarium Power Filter 20 (with 8 added Cobalt Aquatics Ceramic Rings)
Aqueon Submersible 50 Watt Heater
Top Fin Air-1000 Air Pump (with small air stone)
2 small Anubias Nana attached to a piece of driftwood
1 small Java Fern attached to a suction cup along the tank side
2 small Hornwort attached to a suction cup along the tank back
1 male Platy
4 Glowlight Tetras