Do I need a Phono Cable?

you're fine

Maybe.

I have those aq cobras they are good, but I prefer the music hall phono Cable $99

Stay with what you have! Zip for ground is ok!

A low capacitance per meter cable is the best, as well as good shielding. Phono cables are a specific cable and intended for that purpose. They are constructed differently than a regular interconnect. It would not hurt to swap in an affordable phono specific cable. The music hall, as mentioned, is  a good choice. I personally use Atlas Element phono cables. Also, Rothwell the river low capacitance cables work well. 

The thing is, you will always wonder, in MY system, will it make a difference? WTH, do some research, make a choice, buy one, use it, don’t compare it, keep the old one for a spare. You sleep better.

Primary reason for dedicated phono cable is easily avoiding hum, after that you have the design/quality of the cable conductor and jacket.

DIN connector the easiest, ground is in the tonearm fitting and separate ground wire stays within the cable until it separates at the end that attaches to the preamp’s ground. RCA phono cable ground wire needs to be connected to ground both ends.

I used a common phono cable

https://www.amazon.com/gp/product/B000PO1H80/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

while waiting for my high quality Ortofon phono cable, highly recommended by my Blackbird tonearm’s maker.

https://www.ebay.com/itm/Ortofon-6NX-TSW-1010R-Tonearm-Cable-RCA-RCA-Terminal-1-2m-Japan-NEW/1233236...

Changed them, nobody hears a difference. I just moved it to a different arm, again, no difference.

I just bought a 3rd tonearm, it is coming with it’s own fancy phono cable included,

https://www.ebay.com/itm/Mission-Model-774LC-Gimbal-Bearing-Stereo-Tone-Arm-Pick-Up-Arm-Outstanding/...

I’ll move that cable here and there to see if anyone hears a difference. We are all old dogs, old ears, differences in highs we can’t hear? I’ve had young musicians listen, they don’t hear any difference.

btw, that Mission Arm and it’s Jelco version are extremely compact, only 210mm spindle to pivot, and short rear counterweight arm. I will just barely squeeze it onto my JVC CL-P2 dual arm plinth, left side, backwards, just clears dust cover.

I am going to try some Signal cable, reasonably priced that seems worth trying, or I may roll my own using some silver solid core.

So i decieded to roll my own, and the results seem to be positve and better than my AQs.

I used some Parts Connection BL-AG 23awg solid silver core wire, with Deusland 16awg wire as a ground connected to the drain wire of each run. I terminated with KLEI pure connects and WBT 4% silver solder.

Much better and less bright than what I had before, and seems much cheaper than the Furutech i was looking at, seems like at the moment good enough for me.