Black widow tetra

Question
Hi Karen,

I recently purchased two black widow fish from the pet shop and was informed that they were cold water fish. They are the only fish in our tank and we bought the tank at the same time as the fish. The tank is large enough to accommodate them.  Now I'm starting to think that they are tropical fish. One of our fish has already died, and the other one is struggling to swim and has small white spots over  his fins and body. He also doesn't eat. I'm assuming that he'll die too. Is there anything I can do?

If is too late, can you recommend a cold or fresh water fish that is easy to look after and doesn't need so much care in terms of PH level or temperature - would a gold fish be okay? Can one gold fish survive on it's own or does it need company?

Thanks for your help!

Answer
Hi Ali,
Its not the species of fish you have. Black widows are incredibly hardy and easy to care for. But the problem lies when you added them to a tank just setup the same day. See all tanks must go through a cycling phase before they can hold a normal amount of fish. Cycling a tank means allowing good bacteria to develop in the gravel and all surfaces of the tank. They are vital because they remove ammonia that the fish produce. And ammonia even in tiny trace amounts is toxic to the toughest of fish. So you need these bacteria to help keep your fish safe from death and sickness. All newly setup aquariums don't yet have this bacteria and need plenty of time to develop it. In order to prevent fish loss at first with new tanks you must stock it very slowly and its best to have test kits on hand to test for ammonia which is very easy to do. You can get test kits at petstores. Liquid drops are easier than the strips.

With a test kit you would test the water everyday and make those vital 50% water changes whenever the ammonia rises above safe bounds. This will not disrupt the cycling and quite necessary for the sake if the fish.

*When doing water changes, always be sure that the replacement water is treated with a water conditioner and is equal in temp to your aquarium or just a bit warmer.*

*~*The bacteria function like this- first bacteria develop to convert the ammonia into a chemical called nitrite which is still pretty toxic. But later, more bacteria develop to convert the nitrite into nitrate. That's the bacteria's job. Nitrate is not toxic unless in very high concentrations and is removed by your regular maintenance water changes. *It takes about 4-6 weeks for an aquarium to cycle and during that time ammonia will rise and fall and so will nitrite. Whenever your ammonia and nitrite both read ZERO consistently then your aquarium is officially cycled.*~*

I know this all sounds like a lot to take in if you are new at reading this info but it all boils down to these important things to keep in mind-

*All new aquariums need to cycle
*Cycling means establishing the good bacteria that get rid of the bad toxins a fish produces. These bacteria naturally develop in the filter and on all aquarium surfaces on their own and all they need is a food source (ammonia).
*To begin cycling a tank (depending on the size) I would add 1 black widow tetra for a ten gallon tank. Feed the fish very lightly and test the water every to every other day. A water change done if the ammonia goes up or the fish seems stressed.
*If the water all tests out fine Ammonia-0 Nitrite-0 Nitrate-20 more or less then you can add a couple more fish.
*The next day test the water because you may go through a "mini-cycle" where the bacteria have to adjust to the new fish additions. If you get an ammonia spike (which is unlikely) a quick water change and time will fix it.
*After several weeks your aquarium will be cycled and you won't have to worry about testing the water all the time and making emergency water changes.

The remaining Black widow probably won't survive. :( Sounds like he has an internal problem and also has ICK or white spot parasites which look like the fish has been sprinkled with salt. It is easy to treat with the wide variety of medications available but it may be too late already.

Now a little bit about Black widow fish. These are very easy fish to keep provided they are kept in the right conditions. I'm not blaming you at all. You meant well but just didn't get the right info.
Black widows can be coldwater and warm water (tropical) fish. They are good fish for cycling provided the ammonia levels are not allowed to climb during that time.

I tend to not worry about pH when it comes to most all fish. Most aquarium fish are now bred extensively in captivity on fish farms so they are adapted many varying levels of pH and other water chemistry. As long as the pH remains stable and is not adjusted almost all fish do fine at whatever pH you have.

Some really good beginner fish are (but not limited to)-
*Platies
*Black widows
*Lemon tetras

*Danios
*White clouds
*Bloodfin tetras
*Neons
*Corydoras catfish
<Keep in mind this is for a cycled tank>

Goldfish aren't the best fish. Especially for beginners. Despite what most people think, they are not easy to care for. They need a special food and extra filtration and water changs to really thrive, plus they grow larger than most tropical/cool-water fish.

I hope this helped clear up some of the problems here.

I wish you only the best!
Karen~