resilient isn't the word! here's the story, i will embarrass myself here too. about 2 months ago in my 60cm optiwhite, you'll all remember the red eye tetras?....well you see they kinda disappeared one by one, i thought they were jumping out the tank and lost forever. in fact i lost most of the contents of the tank. :? then i discovered the filter inlet had lost the little protector thingy. it dawned on me the might of gone to fishy heaven. never thought nothing of it put a new protecter thing on and away we go. i put the "mature" filter on the new current set up along with the cleaned rean xp2 on discovering problems with ammonia and slight algae (staghorn on filter out let and old leaves of microsorum) problems which were developing i decided i better clean the filter(which had not been done for quite some time let me tell ya) i opened it up, took the trays out cleaned the sponges (which were absolutely disgusting!!!! ) i thought ahhhh, here's my dead fish and shrimps and the last few months crap! washed it all out in tank water. when i went to pour the main compartment on the lawn i was amazed to see....fish!....ALIVE! now believe me when i say i was stunned! 2 months for god sake in my filter. here's what was in it alive (now back in my tank swimming happy, yes happy as Larry! BTW there were others that didn't make it. i think this is where my problems were stemming from (i hope) 3 red eye tetras 2 x SAE's 4 x shrimp 1 x otto now don't shoot me for this, because i already feel bad enough as it is, but im just amazed at how resilient life can be!