Need advice - odd behavior of a molly

  1. M

    Misa New Member Member

    I'm asking for advice or information for my husband and myself. My dear hubby recently got a new tank. He used to have a small tank when he was much younger (early teens). We now have a 55 gallon tank with a Penguin bio wheel filter. We set it up on June 18, let the filter go, added dechlorinating solution and a live bacteria solution. No fish on the first day. We bought 2 gold barbs, a molly, rainbow shark, and a Chinese algae eater on June 19. Everything went fine for 2 days, then a gold barb passed. The other barb lasted 2 more days. On this Sunday, 26th, we purchased and added 5 green tiger barbs and a bumblebee goby. The molly immediately began swimming around with the barbs. Nothing strange Monday. Early Tuesday morning (28) my husband found 1 of the new barbs dead and a second nearly dead. Later in the day we have seen the molly chase and nip the remaining barbs until they were dead. After removing the barbs, the molly swam around like normal for about 30 minutes, swam towards the top next to the heater and has remained there all evening.

    My husband tested the water today with a 5 in 1 strip. I don't know the values, but he said everything was in proper range except the PH which was high at 8.2. We added ph correcting solution. We attempted to vacuum and replace water with a python gravel vac this afternoon, but that was another problem on its own, and ended up replacing only a small amount of water.

    The molly has not nipped any of the remaining fish (rainbow shark, goby, and algae eater). Any information, advice, suggestions are needed and welcomed! Thank you in advance.
  2. el337

    el337 Fishlore Legend Member

    Welcome to the forum :)

    First, I would read up on the nitrogen cycle (if you click on the blue words, it'll take you to an article). This is the single most important part of fishkeeping that will create a safe and healthy environment for your fish.

    Second, I would get the API Freshwater Master Test Kit as the strips are notoriously inaccurate. Also, if the pH is at 8.2, I would stop using the ph correcting solution as that pH is fine and most fish can adapt to it.

    Mollies can be bullies so it's not surprising that they will chase other fish but it could also be because the barbs were already ill/dying so it took advantage.

    What bacteria supplement did you add? You won't want to add any more fish until your tank is cycled, showing 0 ammonia, 0 nitrite and some nitrates using the liquid test kit.

    I would also rehome the algae eater. They get far too large for your tank and get extremely aggressive. And I'm not sure about the goby but I believe they need to be a group. I also don't know how compatible they are with your other fish so I'll let someone else chime in on that.