I use the Tetra Whisper 3i, as it is a bubble type filter and it does not give heat into the tank. The motor (which is the part that gives off the heat) sits on a shelf above the tank and to the side of it, so it does not take the chance of falling into it. The 3i size does not move water very quickly, but in a planted tank, the plants will remove much of the bad stuff in the water in the cycling process if you don't have too many salamanders for the space and you clean the debris from the food and waste often. You can even use a turkey baster to avoid damaging plants and roots. How many gallons is that tank capable of handling? You don't want to have a filter that will be so strong that it will knock your salamanders around. You want to find out how big your tank is and if you think you will have a problem cooling it, find a species that is probably small and aquatic or semi-aquatic so you can use the most water possible in it. I am running into that issue. I am having to increase the water level and add more plants. The more water is in there, the easier it is to keep cool, and the less likely you will have problems with water quality issues. It also helps if you can have it densely planted. That helps with water quality too. Make sure you get a species that can handle those conditions. (a lot of water and plants) Also, don't get fooled by pet stores into buying plants that are not really aquatic ones that end up dying in a few months because they are really bog plants if you are putting them in an aquarium. Go to
http://www.plantgeek.net to find out ahead of time which ones to buy if you are going to plant an aquarium. You may be able to buy them online if not in pet stores or here in the wanted area. I had a pet store that special ordered my Chinese firebelly newts, but due to their condition, and their poor immune system because they were wild caught, I had to go through many deaths before I now have some that I have finally found that are going to make it. You would do well having them shipped from a member in the for sale area. It is easy to place an ad in the wanted area if you would like.
A fan may be fine if you are getting a water dwelling salamander, but if it will be on land it may dry the salamander out. Sometimes a species like Chinese firebelly newts will be on land for part of their lives before becoming aquatic again as adults. If they are in the terrestrial (land) stage, the fan would dry them out too much. It depends on what you get. If you get the species that is aquatic and fill it up so you have a few inches left to the top, you may be able to keep it cool enough without a fan if you don't use a light and don't use a filter with a motor in the tank. If you do use a fan if the salamander lives in the water all the time, it won't affect the salamander but it will keep the temperature lower. Some salamanders need the lower temperature, and some are ok with 78 degrees F. It all depends on what species you get. I would research really well ahead of time! You may save some money and headaches.
Hope I have helped,:happy:
Critter Mom