My aquarium has a high casualty rate. Why?
I set up a 20-gallon aquarium in May this year. I started off with 3 tiger barbs, 2 hi-fin red-eyed swordtails, 2 albino corydoras, 2 red-cross tetras and 2 golden rosy barbs.
Within a week, the 2 albino corydoras (suspected poisoning? due to inflamed, red gills) and 1 red-cross tetra died (it’s stomach was cut open so I assumed it was attacked by another fish).
A week later I added 2 albino sharks and 2 red-cross tetras. They all did fine for over a month.
Then one morning I woke up and one of the golden rosy barbs was bleeding (one the left side by the fins). I isolated the fish for awhile in another tank and treated the wound with medication. When I put the fish back in the tank, the other fish attacked it until it sank to the bottom of the tank.
A few days later, I woke up and one of the hi-fin red-eyed swordtails has died; it had already turned white and was hidden under an aquarium plant. A few days later, I noticed that one of the red-cross tetras has its scales coming off and its tail and fins nipped. I isolated that fish in another tank and treated it with medication thinking it had some fungus/fin rot and it died two days later. Just then my last golden rosy barb had its tail nipped (by the tiger barbs?); it survived though, and the tail has just grown back.
Thursday afternoon last week I bought 2 more additional tiger barbs after reading from a website that their minimum number in a tank should be at least five in order not to be violent to other fish. I also added 2 scissortail rasboras.
However, the following day, one of the scissortail rasboras died, finding it at the bottom of the tank. Then on Sunday morning, I find one of my albino sharks dead. Its belly was bluish-blackish and when I took it out of the tank, it smelled really really bad.
Today I get home and find my last red-eyed swordtail dead, but it didn’t turn white like the other one did.
I have already cleaned out the tank, the filter and changed the water and added water conditioner in it. I feed the fish twice a day.
I’ve been to many fish shops and consulted the people about this matter and one said that it’s the tiger barbs who’s killing the other fish. Also, I only get my fish from two fish stores and both always tell me that my fish are compatible with each other (or maybe they just say that just to earn money from me).
I don’t know what’s wrong. Either my fish aren’t really compatible with each other or I introduced fish too soon.
This is only my second aquarium. My first aquarium was only a 5-gallon one and I took care of 3 neon tetras without any problems for almost two years (until my 6-year-old niece decided to dip her hand into it and killed two of them). Later on I had 3 red platys and they got along fine with the remaining neon tetra (the person I gave them away to said one of the platys got pregnant twice already).
What am I doing wrong? I’m about to give up!!!! I’m ready to get rid of the tiger barbs and go back to caring for neon tetras and platys.
You added in too many fish at once. You should only add in one or two each week. The other issue is that your tank has not been cycled, so this is know as new tank syndrome. Cycling is where your fish poo is converted into ammonia, then to nitrite and then to nitrate. When you have so many fish in your tank as you did, the ammonia level sky rockets to a very dangerous high level, which would explain all your fish death because ammonia is fatal to fish.
Another thing to remember not to do in the future, is to not add in any new fish while it is cycling, and if you suspect a disease, never add in new fish. It will just expose the new fish to the disease, and you don’t want them getting it as well.
You will need to cycle your tank first, it happens naturally, and there is pretty much always deaths from it. Cycling must happen in fish tanks because later on it will convert the bad bacteria into good bacteria which isn’t harmful to your fish. Add in some stress zyme or cycle to kick start the cycling, these products will add millions of good live bacteria to your tank.
Don’t add in any new fish, you should only have a few in there to cycle the tank. Once it is done cycling (when the ammonia and nitrite levels are 0, and the nitrate is slightly above 0), you can add in one or two fish each week.
My aquarium has a high casualty rate. Why?