Phillyfig8 wrote:the set up that he suggested sounds really difficult to setup and maintain. the less water the harder it is to keep balanced. from the pictures of the mudskippers in the wild it looks like they are on a sandy beach. do you have any full tank shots?
The suggested setup might not be very easy to realise if you do not have access to intertidal mud. On the other hand, maintenance is not problematic at all.
The superficial layer (few mm) of mud will ensure sufficient aerobic bacterial activity for nitrification, and I suspect that also anaerobic denitrification occurs below this layer. Furthermore, mudskippers are extremely resistant (I'd say almost insensitive) to ammonia/nitrogen loading. The most important factors are: 1) the possibility to select exposed vs. submersed conditions; 2) presence of moist (> 70% RH) and hot (28-30°C) air; 3) salinity of interstitial water and "tide pool" of 5-20 ppt (salinity fluctuations can be reproduced by adding fresh water; refer to conversion tables at different temperatures to convert salinity to density); and 4) availability of mud: sand is NOT appropriate.
I took those pictures in the wild (northern Australia, Darwin): that is intertidal mud with only a minor sand fraction. In any case, burrows were dug in patches of almost pure mud and silt (absence of visible particles). In several sites P. takita was observed burrowing on sloped mud banks of intertidal waterways (creeks, inlets).