They have a stealth feature that nothing will attack you while riding one. If you attack something, say, a megalodon, the meg will attack once, then leave you alone while you’re killing it. But if you dismount, then get back on, the stealth is disabled. WARNING! NEVER ATTACK CNIDARIA! If you do, you will die and lose your ichthy.
Always put a tracking device on your ichthy. I once had an ichthy called mini on mobile, mini was a good tame, she never failed when I needed her, she was the first way I got to herbivore island, she could take me to all the best hunting beaches, but then one day I thought 'hey mini's such a good tame let's see if I can go around the whole island on her' so I tried I was doing well, I'd already got from my home in the footpaw to the sandspit near the red obelisk, but then mini started to get hungry, I went and looked for food for her and found a moschops, but it didn't give me much meat so I decided to go after a gallimimus it escaped, but when I got back to where I left mini she was gone, no death message no gap in my tame list just gone, for months I searched that sandspit for mini, but to no avail, one day a year after I'd lost her I was running low on tame slots, I knew I had to unclaim her, even now when I visit that sandspit I think I see her but I never do. RIP Mini 🐬💗
MOBILE PLAYERS: I have tested it, and NOTHING, I mean NOTHING attacks you. This includes jellyfish, anglers, mosas, megs, EVERYTHING. HOWEVER. This only applies if you DO NOT attack the thing in question (or ammonites), and in my experience this makes it perfect for scouting out high-level potential tames