It’s prolly safer than the weeds and grass they eat outside that’s had pesticides and fertilizers and other stuff sprayed on it.. I don’t think there would be any issue! Fish are more sensitive than k9’s to anything
Meh, but if you are worried, give him 5ml of 3% hydrogen peroxide and wait for him to vomit. If after 5 min he does not vomit, another 5ml. Repeat that and all of the sudden he will sound like a log chuck rolling down a hill... Probably gonna want the dog outside for that.