Last week, something very odd happened in the five gallon tank I have at work on my desk.  I’d been out of the office the week before and returned last Monday to find one of my Kubotai rasboras was missing. It’s not uncommon for things like this to happen. I couldn’t immediately find its body, so I assumed the snails took care of it.  The other 9 rasbora and the female better were fine, and I did a water change that Monday.  A coworker had been feeding the fish for me and turning the light on and off while I was out.

When I came in on Tuesday, all seemed to be well. I noticed a bit of algae forming though, probably from lack of a water change the week before, so I thought I’d shut the light out for the day and monitor it. I went to lunch and when I returned an hour later, ALL 9 of the remaining Kubotai were missing!

I quickly turned on the light and found one of the poor rasbora sticking out of the female betta’s mouth!  She’d never bothered or chased them before so this was a bit of a shock! It must have been too big for her to eat because she soon spit it out. It was too late though and the little guy was dead.

Searching the tank, I found 4 of the rasboras had gotten through the filter vents and they were swimming above the sponge in the filter chamber. I quickly located two more hiding among the floating frog bit plants. This totaled only 6. I found another dead one stuck to the outside of the vents. With the two dead ones, and the one missing from last week, there was still one more no where to be found! I could only assume she’d swallowed that one and maybe was also responsible for the one missing from last week.

At first, I was pissed off!  I quickly removed the female betta from the tank. Luckily I had some supplies at work and something to put her in for the rest of the day. I had an empty tank at home that she would now be calling home. After removing the remaining rasbora from the filter and putting them back in the tank, I noticed they were swimming near the top of the water as if something was wrong. I decided to remove the remaining six from the tank and take them home for observation.

Once I got home, I put the betta in her new home and I put the rasbora in the tank with my Celestial Pearl Danios, Emerald Rasboras, and Clown Killifish. That tank is pictured below. I’m happy to report it’s been a week since the incident and all six of the Kubotai are doing fine. Also, I noticed the danios and other rasboras in this tank always hid before, but now they come out to eat. I saw a video on YouTube that mentioned how sometimes shy fish will observe other fish in the tank to see if it’s “safe” to come out. Since the Kubotai are always active, maybe the others have taken notice. So, I’ve decided to purchase 6 more for this tank.

As for the tank at work, I tested the water the following day and noticed the Nitrates were high. I thought this was odd since I’d just done a water change the day before, but this might explain the odd activity, especially why the Kubotai were hanging around the top of the tank after I removed the betta. It’s possible that the nitrates were affecting them.

However, this still intrigued me since I’d done a water change the day before. But I was out of Seachem Prime which is a conditioner that removes chlorine and helps detoxify ammonia, nitrates, and nitrites. Instead, I used a different conditioner that removes chlorine only. I can only assume that the water at my work might be high in nitrates. Luckily, I had some more Prime on order! I’ll never use anything else again.

I did another water change last Friday and used Prime. I haven’t tested the water yet, but I intend to do that this week and will probably even test it again before adding more fish to it.