i have never provided hiding spots ie pipe or drift wood for any of my fish
with any big fish water conditions are key
WE DONT KEEP FISH WE KEEP WATER
drift wood rocks and pipes hold all the waste and you dont get to see the fish you keep you just see a head popping out
it also makes fish more aggressive as they defend the spot
See and another point where we differ I guess... I keep fish.. water isn't a living, breathing, thinking being... "keeping water" is as important to me as having healthy fish.. I've rarely lost a fish even the delicate hard to keep alive species.
I have a viewpoint of acclimating it to captivity is priority 1.... getting it offa live foods, or being able to "enjoy seeing it" are all lesser to me vs getting a fish to eat, and show signs of "comfort" in captivity. I try very hard to to come off as "humanitizing" my pets because I honestly don't think they view the world as we humans do ( ie some people dress their dogs ect..) But I've spent entirely to many hours around animals vs humans to not believe they have their own languages, intelligence, ect.. I've found my fish happy and healthiest not just with good water and food but also things in their tanks to encourage thought ect. yes some fish are pretty dumb... but other like big cats and ray, knives.. ime are all intelligent creatures who imo deserve better from us then to be kept in a box of water. I also think a lot of the aggression issues we see in otherwise "predicatable" species relates to environmental and psychological issues more then people want to admit.
Each tank is also very different and each set-ups requirements.. that's not even accounting for the fishes personalities ect... 1/100 things could be wrong but that 1 thing might be what triggers a negative impact on the whole system/set-up. why I'm a firm believer when it comes ot tanks.. if it ain't broke don't fix it.
The best explination/experience I can share in this reguard is I acquired 2 very large tropical gar about 2 monthes ago now... These 2 gar have a laundry list of tank-mates they've killed over years... But in my set-up these two fish are extreamely docile, and in general not aggressive.
Space - this is key to keeping any fish.. we shove big fish in small tanks comparatively. Most fish if you went w/ a 1" rule modified ( ie a 10" fish in a 75 is okay) work out the numbers and you'de be sticking smaller fish in smaller tanks we'de say where to small...
Territory- I look at space and territory very differently.. because some species have small territories so more then one in a large set-up would = their native ranges ect.. fine these types of intermingleing usually work long-term. You also see people ( very common in African cichlid set-ups) put so many into a tank no fish can really claim a territory. I don't agree w/ doing this as while it "works" you end up with the occasional dead fish due to aggression issues (imo that's not working.. the fish are stressed, deaths occur)
Comfort- Do the fish have rest spots? in a bare tank they usually will find the corneres ect... this tells me not only that they are seeking cover.. they are seeking safety. Often times fish get use to this... I have a few fish/species that I know Do not do well. Spiney eels are a wonderful example of a sub-species that really do not tolerate bare tank set-ups... "oh spiney eels just jump"... that is not an answer.. that's an evasion to fixing a very real problem. They require hiding spots or they will seek them out. They don't jump out of tanks because they have "suicidal tendancies" there is something Very wrong in the husbandry practices of their owners... who will keep having spiney eels jump until the understand they need to hide.. or pick different fish.
Food- Back to the gar... predatation of tank-mates w/ gar is a very often founded fear by a lot of their keepers ( I am going to say here that alligator gars are being exclused from these statements as I have never personally owned one, and they are considered by those who have as being the most aggressive species) I personally have NEVER lost a tank-mate to my gar in the past 3-4yrs now of keeping them. I chalk most of this up to my continuing to feed them live fish. These are predatory hunters of fish... its what they do.. and I not only indulge them this but encourage it. I will use minnows on occasion vs goldfish as they are faster and much easily evade the gar then goldfish do. I don't get my jollys ect from watching this, But I do respect the fact a predator needs an outlet.. or they will make/find one. Undertstanding the "nature" of the fish you keep is part and partial to creating a well balanced diet for them not just nutritionally but psychologically.
Even the dumbest animal is going to go abit crazy if stuffed into a "cage" nothing but them in it.. fed the same thing day in and out...no toys ect.. You will see neurotic tendancies eventually... some less problematic then others.
I've had the unfortunate privalage of interacting with large cats, reptiles, horses ect all smart predatory animals and have a hard time not seeing intelligence in some of my fishes eyes... and seen some of the behaviors from lack of "enrichment" in their lives.. I don't want to do that to my fish either. particularly one as large as a RTC that wants to interact with its owner. Both my big cats now want my attention anytime they see me.. yes its mainly food. but one of the big tropical actually enjoys being touched and will swim and brush against my hand before/during/after feedings or just anytime it sees me. Big fish actually aren't hard to train... I look forward to working with mine more in the future.... but we still imo need to respect them as the predetors they are and give them an outlet to be what they are.
keeping a single tetra will often result In its death simply because its a schooling fish... I see no real reason not to think if we don't meet our larger fishes needs besides clean water, good food, space to swim. That they wouldn't also be "inadequetly" tended. Just because it may not school doesn't mean we're giving them everything they need.
Most my fish started with heads popping out.. but I have yet to own a spiney that wouldn't hand-feed. my TSN has recently started begging for food after how many monthes? I have found the more intelligent the fish the longer its taken to "buddy up" with them.