What's going on with my RTS


I have a 20 gal tank with 1 red tailed shark and 4 tiger barbs. (started tank beginning of March) My RTS use to swim around in the open in the afternoon but now we never see him. He has a hollow log to hide in and stays in that all the time. I noticed recently that while inside the log he will rest in the gravel. When he starts to swim he will float sideways a bit before swimming upright. The Tiger Barbs are all doing well and keep to themselves.
I have had an increase in ammonia level recently and can't figure out why. I have not been overfeeding and make regular water changes.
Nitrate - 0
Nitrite - .5
ph - 7.2
ammonia - 3.0

After this last reading I made a 25% water change.
What else do I need to do?


Hello Rharvey and Welcome to Fish Lore!

Tiger Barbs can be a nippy little fish. I have a feeling your Red Tail Shark may be feeling some aggression from them especially at night when the lights go out. (although I can't say for certain)

Another reason for his behavior could be due to poor water quality with a rise in ammonia levels. For one reason or another, either your tank was never cycled or it's going through a minI cycle.

I suggest daily water changes of 30 to 50%. Add some Prime or Amquel + to detox the ammonia for 24 hours until it's time for the next water change. Keep up with the daily water changes until you have 0 ammonia, 0 nitrites and under 20 nitrates. At this point you've regained your cycle.

Prime and Amquel + are two of the most recommended conditioners on this site for detoxing ammonia and just an overall great conditioners, removing chlorine, chloramines and so on. See link below:

As to why you are seeing increased ammonia:
Are you doing gravel vacuums periodically? What type of filtration are you running on the tank?

If you would be so kind as to complete your Aquarium Profile Information it will be a great help to others with their responses. To access the Profile, click on My Settings in the blue bar close to the top of the screen. In the drop down box click on Edit Aquarium Information.

Best wishes!


I do not think it is the Tiger barbs aggression.
Will be good to know the size of the RTS.

My Rainbow Shark tend to be the showing it aggression to the Tiger Barbs though.

I think RTS should be similiar to Rainbow where they prefer to be more active at night or during feeding time.


My rainbow is active all day. Sometimes I think with the sharks, as long as they have ample roaming area, they will be healthier and happier.

When I had my rainbow in a 20 gallon, he was definitely not as happy. I'm sure he was cramped. Now, he's in a 46 and I've seen growth and he just looks really filled out now.


welcome to fishlore!!!!
I also don't think its the tiger barbs I think its an uncycled tank with super high ammonia
getting one of the products ken mentioned, with daily water changes until the tanks cycled, will help everyone....but warning, once they start feeling better, they will clash with lack of tank space as both are territorial about having enough room....but with hiding spots on the bottom, your shark may behave himself but not positive....cycling the tank is best to get done now so you don't loose any fish...good luck!



When I first got my Rainbow Shark (same family as the Red Tail Shark RTS) I didn't see it for 6 weeks and then one day he/she just appeared. He hasn't gone back into hiding since. 3 years old and 6". I got it when it was a 2" juvenile.

A larger tank might be something you should consider, I usually recommend that they go into 55 gallon or more. (although I've seen information otherwise for smaller tanks, I don't agree). As the Shark matures chances are greater that you're going to see more aggression from it.

I really like to see Tiger Barbs in a species only tank.

  • Thread Starter


Thank you all for the advice!!
I just completed another water change and gravel vac. All the fish are still with me. My RTS did make an appearance while I was doing the water change and seems to be doing ok. He is small, around 2 1/2 ". All the fish in the tank are juvenile.
I have a Top Fin Filter model 20. Do I need I better filtration system?
I'm really enjoying the tank and would love to have a bigger tank soon, but I want to make sure I can master this one first. Thanks again, this site has been a wealth of knowledge!!
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