puffer and tank mates

Question
Hi Karen
I'm writing from Mexico, sorry for my English.
I have a 20G tank with 2 beautiful 2" Angelfish, 1 algaeater and 1 plecos (small). Everything going quite ok. I just bought with panic 2 puffers about 1.5" big, I read some times they bite others. For my luck the Angelfish knew right away how to keep them in line. But....one of my puffers lost its very intense yellow color turning quite black also its belly...is this a sign of problem ? Is sick ? I read they need salt, but what about the others if I add salt ?

Please answer me also at my personal e-mail address.

Thanks in advance !!

Ricardo

Answer
Dear Ricardo,
No need to apologize!

This is very hard for me to say because I'm not sure of the exact species of puffer you recently brought home. Some pufferfish indeed require salt in their water and these puffers are known as 'brackish' ---Brackish water is a mixture of freshwater and oceanwater. To duplicate this you must use marine salt and not just aquarium salt, because just aquarium salt (the kind sold in little boxes) doesn't contain special trace elements and minerals like the marine salt does. In order to create brackish water properly, you must have marine salt on hand. Getting the salinity level correct means using a special measuring device called a "Hydrometer" which comes in two different types. One is free-floating similar to a regular thermometer and the other is a standing type that you fill with your aquarium water to measure the salinity. Salinity is also called "Specific Gravity" and measurements typically appear like this for example- Figure-eight pufferfish prefer a salinity level of 1.005
Where the Ceylon Pufferfish prefers a salinity of 1.015

Some pufferfish live half their lives in brackish water and then require to be moved to fully marine conditions.
And then there are some completely freshwater pufferfish that do not ever require brackish conditions.

Unfortunately, despite all of this. Angelfish and your algae eaters won't do well living in brackish water and Pufferfish really do best in an aquarium just for them so all their special needs and requirements can be met so the puffers can live to their full potential.

The one puffer you described as having lost his color could be related to the water quality. It would be most excellent if you could test your aquarium water for ammonia,nitrites, and nitrates. In healthy established aquariums, ammonia and nitrites should always be-0 and nitrate should be 20 or less. If this aquarium is relatively newly setup, then the special beneficial bacteria who control ammonia and nitrite levels aren't yet fully colonized and water changes are required to keep the dangerous ammonia levels at bay until the tank establishes fully.

He could have also changed color as a sign of his mood. Many fish change color if they are frightened or simply unhappy. Knowing your puffer species will be best in helping you figure out what the problem may be.
A great pufferfish care website called- "Pufferresources.net" may help you both to indentify your puffer species and it gives plenty of info on the proper care of your puffer as well.

I really hope this helps and feel free to write again if you have anymore concerns!

Best wishes and Happy holidays!
Karen~