Never kept one of these but I believe it gets bigger than the Fire Eel, so I would think 75 gallon would not be ideal. Sorry mate. Im looking for a spiny eel myself, Have a look @ Black Spotted spiny Eel, might be more suitable.
Wow Mastacembelus dayi is a gorgeous spiny eel! Thanks for telling me about them! Do you know what size they max out at? Some say 12" some say 20" ..... >.>
tyre tracks do get very large and have a massive girth when adult. When I bought my 21 inch fire eel the guy had a 24 inch tyre track that was so thick it was untrue. That being siad it would take it a long time to get to anywhere near that size and a 75 g would suit for a good while if you could provide a bigger tank and if not I;d take it off your hands hah a
thats why I went from a 4ft to 6ft tank for my Datnoid. You might do the same eventually as you get more attached to your fish. Of course the Bigger the tank the better. IME its better to get the fish that you want rather than an alternative, in my case I know my LFS will take it back or I'll get a bigger tank if the its worth it. I did the latter 
I suggest just give it a try and you can decide for yourself eventually as they mature. I never really kept a TireTrack Eel but read about a guy with a 34" Tire Track from another forum. Theyre very flexible, just Im not sure having that size fish in a 4ft tank is a good idea.
Im that type of guy that will get the type of fish I want even when my tank is not big enough for a full grown and will figure out something laterthats why I went from a 4ft to 6ft tank for my Datnoid. You might do the same eventually as you get more attached to your fish. Of course the Bigger the tank the better. IME its better to get the fish that you want rather than an alternative, in my case I know my LFS will take it back or I'll get a bigger tank if the its worth it. I did the latter
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