I used an outside food source but i filtered through 2 nets to avoid them so unless they were these microscopic looking things i didnt put any in that way. Im pretty sure it was the plants, i gathered them from the canal out back, i QT them for 2 weeks in a 5 gallon bucket outside, rinsing them every other day and changing their water, i guess this would be adequate for an adult, he could eat the newly hatched ones that may have been dropped off JUST before introduction but not for fry. I was so thurough though, its hard to know i somehow missed them.
All 8 fry i siphoned into a 2.5 last night have survived overnight, they are picking at the marimo ball this morning, thank goodness they were 2w old before the dragonfly nymph took most out, easier to see and hardier. Thank you :)
Edit: the picture is from the bucket i siphoned it into it was alittle more then a cm long, alittle less then an inch, pretty large, and there was 2 more of its size, then a few smaller ones. discusting little things!