Passive tamed with element. Pretty much the same as passive taming a Diplo, they will attempt to play with you by knocking you back while doing 0 damage. Best strat is to wait for it to get stuck somewhere or kite it by staying next to it. The more element it ask for the more effective that feeding will be, typically I’ve seen them ask for 1, 3, 5, or 10 element at a time in that cycle on a slightly boosted server but could be more on official. Bring plenty of element as they do take quite a bit the higher the level. Thankfully element farming is easy, Saddle is unlocked at level 120 so no boss fight needed to get it, however you will have needed to do the Overseer, Rockwell, or Master controller in alpha, plus get a chibi to max to unlock the saddle.
First, make sure no voidwyrms are nearby, as they will try to kill you. Next, pet the Astrodelphis. Finally, put element in the last slot of your hot bar and start feeding it to the Astrodelphis. Thanks for reading my tip!
U have to pet it and feed element. The amount of element goes up each time u have to feed, but the taming bar will fill up faster. Easy element u can gather by using an anky or pickaxe on the blue crystals in the space between the bridges. In the center of the map
(I’m writing this off my own experiences from taming it, hopefully it’ll be helpful to you, the reader!) For taming you need to trap it (most preferably 5 gates in length) it can be very difficult to trap but as long as you get a straight angle you should be fine. They can attack and their attacks have massive knock back (making trapping more difficult). For taming you need to pet it (sometimes more than once) and then feed it element which increases each time you feed it (1, 3, 5 and 10 then it resets back to 1) Make sure you keep petting and feeding since it can loose like 30% if you stop for a short time. Element can be found during purple drops in the blue-ish area. Hope this helps.
BEWARE OF FOOD DROPPING. Not sure if it is a glitch but within a minute or so of taming it was starving. Filled with with a few stacks of meat and it ate them all and starving within another few minutes. Bring extra meat.
What I do... I use Helena to scan it to see its lvl bc I have trouble with the spyglass on space biome..I will aggro it and lure it into the bridge and take it up a bit so it stays out of the space biome and not have to worry about voidwyrms... once it is where I feel is far enough I will tek speed run away and leave render...I will then pet and feed it