We have 2 tadpoles with legs and 2 baby frogs we found in a pond. Do I need to buy a filter for their tank?
Tadpoles poop a lot and this builds up quickly. While a filter is not mandatory, if you do not get one the water will get very messy quickly and require cleaning and changing of the water much more frequently. And make sure that if you do get a filter, you clean it and replace the filters on a regular schedule otherwise they will lose effectiveness. Here is an article with some additional information: http://www.suttonmass.org/animals/frogstoads/tadpoles/tadpolewaterfilter.html