YES, if you can remove both him (in the QT tank), and the entire tank (emptied), that's what I'd do.
Put him in the 1L, and transport him that way.
Empty the larger tank, and leave it in your car for the duration.
Here's an example of a common cockroach pesticide, called Demon EC
- Active Ingredient(%): Cypermethrin Technical (25.3%)
- Highly toxic to fish and invertebrates. Practically non-toxic to birds and bees.
- Invertebrates (Water Flea) LC50/EC50 0.00125 ppm
- Fish (Trout) LC50/EC50 0.00092 ppm
- Fish (Bluegill) LC50/EC50 0.0018 ppm
- Environmental Fate: Not persistent in soil or water. Immobile in soil. Sinks in water (after 24 h).
LC50 means "lethal concentration required to kill 50% of the population" during a given time (usually 4 hours). So exposure to even a TINY bit is capable of killing fish. I'm paranoid, and my motto is better safe than sorry. So if you have a way to move EVERYTHING fish related outside for the duration, that's what I'd do.
When you return.... What's the weather like there? If it's not too hot/cold, ask the pest control ppl if it's OK to leave the windows open awhile to ventilate the premises. If they say it is, I'd do this.
How bad is the roach problem? In the future, maybe look into ways to get rid of them that don't involve spraying?