here you go, lauras write up which helped me loads!!
"It's more what you want NOT to see. Here are some of the main things that would be a turnoff to me. Note that if you're rescuing bettas, it's a whole different story. Virtually everything below is survivable and sometimes completely curable. If you are okay with taking on a betta and spending at least what it's worth (possibly more) and several weeks trying to cure it, then accept that it may never look or act completely normal - then most of these are not going to stop you. But if you're looking for a pet that will be healthy from the start, you should avoid bettas with these indicators:
- Seriously ragged fins. This usually indicates fin biting (it's a nervous habit caused by boredom and stress, it sometimes clears up in a healthy and enriched environment, but some of my rescues still do it in proper tanks after well over six months away from pet store cups.) If the edges are black or white, it's bacterial finrot, which is difficult to get rid of and usually a sign of consistent poor water conditions - this means the betta probably has a plethora of other poor-water-quality health complaints which may show up (fatally) months later.
- Curled edges on a veiltail's tail. It's not an absolute do-not-buy-this-fish, but it's a warning sign. When a veiltail's fins have been badly damaged and have healed, the rays do not grow straight, resulting in curled-up edges and bent rays in the fins. It may have been caused by fight wounds, in which case you'll never have another problem. It can also be a sign of a fin biter. Fin biting is not life threatening, it appears to do no serious damage but the bettas always look awful. If the betta is active and looks otherwise healthy, and I liked it, I would buy it anyway.
- Cloudy or missing eyes. Cloudy eyes is usually another indicator that the betta has been exposed to consistent poor water quality. They're one of my favourite issues to rescue, as they usually respond to treatment and even if the betta can't see, it can have a happy life. If you just want one betta though (dream on spish!) and you want it to be a healthy one, watch out for cloudy eyes.
- Lethargy. This is the worst - a betta that lies on the bottom or hangs motionlessly at the top. Usually lethargy is caused by serious depression - the sort of thing you'd get by locking a human in a jail cell for a few years and only interrupting the monotony of sitting there to poke food through the bars. If it's just depression, it sometimes goes away after you put the betta in a healthy and enriched environment (as with fin biting), but it sometimes won't. It's also an indicator of more serious conditions, and sometimes it's the only sign, so unless you're out to rescue, it's best to avoid lethargic bettas.
- Refusal to eat. As above it can be caused by depression, but also as above, it often means there is a more serious condition. If there are water-swollen pellets on top of the water that have not been eaten, be wary. If it's just one pellet he might just have missed it, but if the full meal of four or five has been ignored it's a fair sign that the betta is not well.
- Clamped or twisted fins. The pectoral fins (the swimming fins just behind the gill plate) are usually fluttering in any betta that is actively swimming, and if you tap the side of the cup, they should come out and start fluttering to help the betta hold its position. If you have to swish the water to make it flutter its fins, it's probably not healthy. A veiltail with a twisted tail is probably not healthy either, although if it flares readily and follows your finger, it is probably okay.
- Swollen abdomen. A slight curve to the belly is normal in a healthy male. A bulge is not. It indicates either dropsy or constipation. These are both diffucult to cure and can dog you for months. Sometimes no matter what you do, you still lose the fish.
- Obvious diseases. Evidently if the betta is covered in slime, has ich, or its mouth is rotting away, do not buy it.
- Septicaemia. This is the end of the life of a betta that has been exposed to poor water quality for several weeks or months, and there is virtually nothing you can do to save it. I have given up rescuing bettas with septicaemia as even bringing out the heavy cavalry (a full course of antibiotics) usually has no effect. My money is limited and it's better spent on a betta with a chance to survive and be happy. Signs of septicaemia are missing scales (several on each side) with red spotting where they should be, red spotting on the sides between the scales, red streaks in the fins and red spots on the tips of fin rays with obvious finrot. It is almost always accompanied by clamped fins and refusal to move or eat, often with the affected fish resting on the bottom and making little attempt to swim if disturbed. It may show dropsy, and sometimes other opportunistic diseases such as columnaris or ich. By the time they are acting like this, they are suffering from multiple organ failure, and there is absolutely nothing you can do. Obviously red marbling is fairly common - if the red markings are even all over and the betta is not acting extremely ill, it is not septicaemia. If the red markings are shiny like glitter, it's an iridescent wash, not septicaemia. The red spots are blood, so if they look nothing like blood, it isn't septicaemia.
What you DO want:
- Bright and alert expression. If you lean in close or put your finger on the glass, a healthy betta will normally show interest, especially in a bare cup with nothing to occupy it. Most bettas will track your finger with their eyes if you move it above the surface, as they are used to a human hand dropping food.
- Fin movement. The pectoral fins should be moving all the time when the betta is active. It is also normal for the other fins to move around a bit. If they are held stiffly, this is a sign of some discomfort although it is possibly just poor water quality stress.
- Willingness to flare. It will probably ignore the betta in the next cup because it's been sitting next to him for a while, so he's boring. Switch the cup beside a betta you're interested in to one containing a different betta, preferably one of a different colour. The betta you're looking at should respond to the new scenery by flaring at him. This is not an absolute requirement but showing natural behavior (even in such an unnatural environment) is a sign of health.
- A bubblenest in the cup. Not an absolute indicator either, but a general sign that he's healthy, because a sick betta just couldn't be bothered most of the time. (If it's not present this is not a problem, if it's there, it's a plus.) "
