Looking for advice on a Poly Tank Build

[Disturbed.)]

Hi all. I'm planning a new tank and was hoping for dimension and stocking advice. I've built quite a few tanks and have kept a metrics blank ton of fish but have always wanted to have a poly tank.
I have a few options with the glass I currently have and a few different placement locations but all have footprint limitations of one form or another. Since I can always get more glass, let's start with current stock that may or may not end up in this tank based on your personal experience and go from there.
Option 1
I have 2 breeding pairs of Rio Negro Heros Notatus Severum. One pair needs a bigger home. So I had planned on cutting apart my 4' 120 and making it a 36X48X24 and adding only the 2 Senagal Bichirs that were brought to me for rescue last week. Cool but they are rare fish I'd rather not see a bite taken from nor their breeding reduced but that tank will still fit were it used to sit in my fish room. Could I or should I still add more bichirs to calm aggression? Thinking Delhezi might be as big as I could go with the Senagals and Sevs
Option 2
I have the glass but would need to relocate my grow out rack to build a 72X31.5X29 tank with about 15 gallons of weir space "the bottom pane I have is tempered and 76.5 long". That space and tank were originally planned for a planted discus tank. So if the bichirs go there who should I add to the mix? Waste of a taller longer tank the bichirs don't need because of the depth limitation?
Option 3
There is space in my bedroom where the temp 75 is holding the Sevs to build a 48X48X24 tank dedicated to polys. What could I put in that? I've always wanted endlis but have heard a few cannibal horror stories.
All advice thankfully taken but if you have a suggestion based on experience and not just "if it were me I'd" please let me know what you tried and how it went in more detail on here or in pm.

 

[Disturbed.)]

My answer came to me, though not the way I'd hoped. The male severum decided to murder his mate after several years of producing fry. So they won't be affecting this build anymore. Rescued an ornate and a couple delhezi last weekend and they should be fine for life in a 30.5" inside wide tank.

 

[kewpiefishypewpie]

Sorry to hear that! My Heterospilus Obscura murdered his woman recently too. Those poly's you mentioned will undoubtedly be fine for life in a tank that wide, some people would even put lower jaws in a tank that size so upper jaws definitely will be okay.

 

[Disturbed.)]

I don't know why it never crossed my mind before but I have a drilled 125 that isn't in use and just taking up space in my shed. So I could cut it and the 120 apart to build a 72X48X24. Sounds like a great footprint for a poly tank.
Anyone have experience trying to maintenance a 4' deep tank? Would you even try to hard or soft scape it? What would you stock it with besides Bichirs? I'm thinking 8 clown loaches maybe an Oscar. Wound an Endli eat the Delhezi?
Thoughts?

 

[The Masked Shadow]

Bichirs do not go with loaches. They do best with fish that are large enough, or intimidating enough to not fit in their mouths. However, it is hit or miss with Oscar’s - don’t recommend. Top water fish are the best, so something like a group of large topminnow/small gar. Bichirs wont eat bichirs as long as they are in the same general size. A wide tank is much more important than height. I wouldn’t suggest a 4 foot tall tank.

 

[Disturbed.)]

In general when talking tank dimensions depth means front to back not top to bottom, that's height. Sorry for any confusion there since I did say 4 foot deep. So the tank would be six feet long left to right, four feet deep back to front, and two feet tall.
Clown loaches are on pretty much every bicher tank mate list. Nipping aside would an Endli really try to eat a fish a foot long with that much girth?
Yeah I'm really iffy on the Oscar. Any suggestions for a cheap top water fish that won't outgrow the tank or harm the bichers is what I'm looking for.

 

[The Masked Shadow]

In general when talking tank dimensions depth means front to back not top to bottom, that's height. Sorry for any confusion there since I did say 4 foot deep. So the tank would be six feet long left to right, four feet deep back to front, and two feet tall.
Clown loaches are on pretty much every bicher tank mate list. Nipping aside would an Endli really try to eat a fish a foot long with that much girth?
Yeah I'm really iffy on the Oscar. Any suggestions for a cheap top water fish that won't outgrow the tank or harm the bichers is what I'm looking for.

Then that would be a perfect tank size. 4 foot back to front is good. As for the clown loach part, I wasn’t thinking the tank dimensions were like that, so yeah, Clown loaches are a good choice, however pure Polypterus and a top water fish is better imo.

 

[Disturbed.)]

With it only being 2 feet tall what would you suggest for top water? Being that shallow the fish are going to mingle water levels no matter what I'd think? I know a lot of people keep Gar with them but hell, even the smallest Gar will top 2 feet of half mouth. It's only going to be 360 gallons if I keep no freeboard and only 1/2 glass so tank busters like them are out. I'll probably build the tank with 2 or 3" of free air above the water level further limiting different fish to stay at different depths. That's an easy design change though if it will allow a better stocking

 

[The Masked Shadow]

I have a poly tank that is 18” tall and the only ones that go up are the del (rarely) and the Senegal (the whole day). Besides that, the mokele and Palmas chill under driftwood and only go up to snag a breath. I was going to do Striped Pike Characin or Marble Gars, but tank size for me is to small. Your tank is quite big. Hendre twentyleagues Deadeye

 

[twentyleagues]

Anything to big to fit in a polys mouth is usually safe. Loaches would be fine as long as they meet that criteria the entire time. Most of the time it's hard to find large clown loaches so people get small or medium ones and they take forever to grow. If you put medium loaches with small polys those polys will easily catch up and pass the loaches before you even see any difference in loach size. Typically if a poly eats a loach you are going to loose both fish. The loaches spines will stop the poly from swallowing it causing the poly to drown but probably not before the stuck loach dies. I have seen some polys take a swipe at larger fish but if you feed them well it's usually not an issue, they tend to be lazy fish less fight from the food the better.

Depending on what polys you are planning on keeping things like butterfly fish or larger barbs and tetras work well. I've seen alot of lower jaw keepers keep gar with theirs seems the gar spend as much time on the bottom as do the polys though. A thought I had (I keep all upper jaws) was to get some archer fish haven't done it yet not sure if I will or not we will see.