something is wrong with my fish

I recently set up a new 30 gallon tank (fresh water). I don't have any prior experience of fish keeping but I'm trying my best.
After completing the silent cycle I introduced 2 red finned shark, 2 albino red finned shark, 1 silver shark, 2 tiger shark (one black and one white). These belong to the minnows fish family I think and I don't know their actual names but this is what the pet store guy told me. I also added 2 other fishes that the pet store guy said were crocodile fish, but they are some sort of small pleco fish species. They are all small (2-3") except for the tiger sharks which are about 6" long.
For three days everything was going great, but this morning I found that the two red finned sharks are constantly nipping one of the crocodile fish. The fish seemed really helpless and frustrated so I removed it from the tank. The two red finned are not bothering the other crocodile fish, however I noticed one of the red finned is extremely agitated and it's fins and tail are almost transparent and it tried nipping others too, to which others responded aggressively. After carefully watching all other fishes I found the same thing with another albino red finned. Their partners are all healthy relaxed and colorful and don't seem worried. But this red finned and albino red finned have lost color and are agitated a lot, doing crazy swimming all around the tank. They ate all right when I fed them but I don't know what else the problem is. These two ill fishes are smaller than their partners but they got along well until now.
I don't have much knowledge on fish keeping and just recently started out. Please advise me what to do.

 

UPDATE: my crocodile fish just died. I feel very bad. Please help

 

Pls separate ur albino red and normal red sharks
never keep them together everything will be fine

 

Pls separate ur albino red and normal red sharks
never keep them together everything will be fine

Post edited. Please keep your responses on forum as taking them off line defeats the purpose of discussing topics via the forum. Thanks.

 

They r both of labeo species and can't be kept together
they will fight together and start nipping fins of each other pls separate them earliest I hv read above in the book I hv
regards

 

thanks
i'll do that and let you know

 

HI Abhilash,

I'm sorry you're having issues with your fish. I have a few questions:

1) What did you do for your "silent cycle"?

2) Do you have a water testing kit?

3) Could you take/find a picture of your "tiger shark" so that we know what species it is as I've never heard of one.

4) Do you know about the nitrogen cycle?

5) How quickly did you add all the fish? Did you put them all in at once?

I think the main issue is that you have too many "sharks" in your tank and they are all aggressive species. They are probably suffering from stress and the water quality is probably not too great because there will be too much ammonia. If you can I would return all of the sharks, that is the red tailed shark, albino red tailed shark and the silver shark as I don't think you're tank is big enough for any of them.

If you want you could possibly keep one red tailed shark OR one albino red tailed shark.

Hopefully someone else with more experience with your fish species will come and give you some advice too.

 

Abhilash, I suggest you return all of your fish and perhaps start again with some more suitable fish for your tank. If you need anymore advice you could start a thread in the stocking area of the forum and there will be loads of people who can give you advice

Sent from my D5503 using Fish Lore Aquarium Fish Forum mobile app

 

Just to add my two cents; I wouldn't listen to pet store people. They're usually just out for profit, unfortunately, because one would hope they would care about the creatures they're selling. While yes, one should always do independent research, it really sounds like your pet store led you wrong. Sorry about that

 

sorry guys for the late reply
but after I removed the ill crocodile fish everything went back to normal
I did some research and now can identify all my fishes thankfully
the crocodile is actually a sailfin pleco and should not be kept together
once the smaller was gone everything was ok
the problem with the red finned was too much heat
I didn't have a thermometer but once I brought the temperature down all the fishes were ok
I have 8 fishes in my tank now and they are all healthy and not aggressive to each other and hopefully not stressed either
thank you all

 

As already said, your tank is not big enough for the fish you have. You either need to be thinking about re-homing all your fish or getting a much much bigger tank

Sent from my D5503 using Fish Lore Aquarium Fish Forum mobile app

 

As already said, your tank is not big enough for the fish you have. You either need to be thinking about re-homing all your fish or getting a much much bigger tank

yes I have been thinking the same. I have set up a new tank which is going through the silent cycle now and after that I'll move some fishes into it.
Thanks

 

How big is the tank? And what are you doing for your "silent cycle"?

Sent from my D5503 using Fish Lore Aquarium Fish Forum mobile app

 

My new tank is also a 30 gallon tank. I don't have the required space for a 55 gallon.
For the silent cycle, I add gravel and water and run the filter for 2-3 days.
We have borewell ground water here so I don't have to worry about any added chemicals in it.
My friend gave me a plant called Indian swamp weed with some fertilizer tablets. I plant them and observe it for a month and if everything looks okay I add fishes.
I don't have any water testing kit, I just observe if the plant is fine and introduce fishes after a month.

 

plants and fish are not the same you do know that. plants can easily grow in normal tap water. they are way times more adaptable then fish so you shouldnt be using it as a indicator that you water is fine for fish.

no idea what a silent cycle is but I have heard of a fishless cycle (if that's what you mean) then you will need to use fish food or ammonia (as a food source for the bacteria) and some live bacteria such as Tetra safe start. as said, your tank is not suitable for those sharks. since you're a beginner I wouldf advice getting easy to care fish like barbs, tetras, cories etc

 

your tank is not suitable for those sharks. since you're a beginner I wouldf advice getting easy to care fish like barbs, tetras, cories etc

The pet store guy said that sharks are very robust creatures and can withstand anything and that's why I brought them.
I can exchange them for barbs. But will it be okay if I just keep one red finned rainbow shark and one columbian shark ( I thought it was called tiger shark, my mistake)

 

30 gallons is way to small for sharks. you can't have any sharks in a 30 gallon tank

The pet store guy said that sharks are very robust creatures and can withstand anything and that's why I brought them.
I can exchange them for barbs. But will it be okay if I just keep one red finned rainbow shark and one columbian shark ( I thought it was called tiger shark, my mistake)

Also as I forgot to mention. Ignore the people in the pet stores. They just want to make a profit. I wouldn't be surprised if they told me that I could have 5 Discus in a 10 gallon tank with no heater and filter.

What you should do is visit the store to see which fish you are interested in, then ask the store people what the fish is called. Then go on the Internet and research on what the care requirements are for the fish you are interested in. You can read articles or talk to the lovely people on fishlore. Then once you are positive that you can take of the fish properly. Then you buy the fish. Done.

 

Unfortunately I have to agree..
Not only is your tank too small for a shark, but you also have too many living together..
You should post pictures of your set up