4 goldfish and 1 betta

Question
hi,

i've made this stupid mistake of keeping 4 gold fish and 1 betta in a 18 gallon tank. I know this is not sufficient quantity for a single fish but i found out a little too late. Now my fish have tail rot to start with, it happened last week and i had changed the water, i have a water filter in place and the temperature is consistent around 27 degrees, after which the tail rot stopped. Five days later the their tails started to rot again, could see some green and alot of brown spots around the aquarium glass, bottom and on the plant leaves and decorations.

I have again carried out a 50% water change, i don't have a water test kit for now so I really don't know the parameters of the water, i am learning as i am facing problems. I am thinking of making bigger tank but right now I am stuck with work and don't have the time.

1. I need to know, how to stop the tails of all the fishes from rotting.
2. If I change 50% water every 3-4 days will that be good.
3. I only feed them once a day with freeze dried bloodworms.
4. How much time is required for the tails to grow back again.


Thank you.
Regards
Osman

Answer
Hi Osman!

#1 Answer: Separate the fish with fun rot from the ones without it. This will hopefully stop it from spreading. Make sure you change the water too to remove the rot bacteria. Try the Tetra LifeGuard. It is like an All-In-One cure. It's available at Petsmart.
#2 Answer: Yes! Changing the water will help significantly.
#3: Blood worms are good but make sure not to over feed or it will cause the swim bladder disease and constipation and other negative effects.
#4 Answer: it really depends on how fast the fish recovers. In other words, results may vary. If I'd recall, mine fish had their fins back in about 1-3 weeks. Try the API Stress Coat. It will boost the healing process and heal the fins as well. Also, it can remove stress up to 40% (scientifically proven). You may also try the API Stress Zyme which is like beneficial bacterial which will eat away the harmful micro organisms in the water and ammonia.

All these items are available at Petsmart.

Hope this helps! XD
~Sam