First, a heads-up. For oddball emergencies, you're better off posting directly in the oddball or predatory fish sections.
I have no idea what an "NF" gar might be. There are literally dozens of species called "gar", ranging from marine needlefish through to freshwater characins. The true gars are the marine family Belonidae, although the name is widely applied to members of the North American family Lepisosteidae. It really shouldn't be applied to the freshwater characins like
Ctenolucius hujeta, which are better described as pike characins. You might find all this pedantry pointless, but it actually matters a great deal. Needlefish, North American gars, pike characins, etc. all have very different needs, so the sooner we can identify the fish you're talking about, the quicker we can offer useful help.
Now, let's review some basics. You shouldn't be feeding them live feeders at all. None of the gar-type fish need feeder fish, and none of them benefit from being given them. The risk of introducing parasites is (hopefully) well known by now, but additional problems come from the fat and
thiaminase in these fish. If you were to feed goldfish or minnows three times a week for a year, you would almost certainly be causing a vitamin B1 deficiency. Since this ultimately leads to things like damage to the nervous system, things like blindness, loss of swimming ability, and muscle spasms would all be entirely consistent. Indeed, I'm increasingly convinced that many of the "sudden deaths" observed in predatory fish come down to this problem.
You need to feed predatory fish a variety of foods. In cases where live feeders are being used, these have to be home-bred, gut-loaded livebearers or killifish, or possibly cichlid fry (though the spines on these make them risky). These fish lack thiaminase and do not contain much fat. The best invertebrate live foods are earthworms, which you can either collect yourself somewhere safe (i.e., not sprayed with pesticides) or else buy from a bait shop. River shrimps contain thiaminase, so have to be used sparingly, though they are easy enough to gut load with flake. Feeding safe live foods is expensive -- which is why hardly any non-expert fishkeepers bother -- and it is almost always better to switch your predator to dead foods. This is possible with virtually all predatory fish; the difference between predators trained to take dead foods and those that only take live feeder fish is usually that the fishkeeper is too lazy to bother (or just prefers to watch one fish kill and eat another). The number of traded fish species that genuinely need live feeder fish I could count on one hand, and none of the "gars" belongs to the list.
Training predators to take a variety of frozen foods whenever you offer them is key to long term success. By forcing the predator to eat things you choose (rather than the predator forcing you to keep buying junk feeder fish) you can ensure a healthy, balanced diet. In
this video I'm hand feeding my pike characins some tilapia fillet. As you can see, they happily take the food. I can offer them regular (daily) meals and this also has the benefits of minimising intraspecific aggression and since they know food is offered every day, they don't bother their tankmates either, some of which are rather small. Indeed, they even copy the other fish sometimes, having the occasional go at things like cichlid pellets!
At least some gar are gregarious, and water chemistry is an issue with some species too. Review those aspects. Needlefish for example often do better in slightly brackish water, even though it isn't strictly necessary. On the other hand, keeping the characins in slightly brackish water won't do them any good at all. Pike characins need water that isn't too warm and has plenty of oxygen. North American gar may be either coldwater or tropical fish depending on the species. Choose appropriate tankmates; almost all gar are peaceful and tend to be bullied when combined with big cichlids or catfish.
I hope this helps.
Cheers, Neale
I knew something is wrong a couple hours later when I check back on him he was twisted in a shape of a U. He looks week, but when you knock on a glass or try to pick him out with a net he swims away normally (straight shape) but as soon he stops turns in to U shape again.
